Patent Description:
The subject matter described herein relates generally to battery technologies and more specifically to current collectors.

Lithium (e.g., lithium-ion) batteries typically include an electrode formed from lithium metal. For instance, lithium metal may be used to form the anode (e.g., negative electrode) of a lithium battery cell. Lithium metal may be an ideal material for the anode of a lithium battery cell due to the high specific capacity of lithium metal. Notably, at approximately <NUM> milliampere-hours per gram (mAh/g), the specific capacity of lithium metal is more than ten times higher than that of graphite, which has a specific capacity of only <NUM> mAh/g. Document <CIT> discloses a method of forming a battery cell, wherein the method comprises providing a current collector and a protective structure that comprises a polymer layer and a single-ion conductive layer, and then intercalating lithium between the collector and the protective layer. Document <CIT> discloses a process for forming electrochemical cells with a liquid electrolyte comprising the in situ formation of a lithium electrode that is deposited, upon charging of the cell, between the current collector and a polymer layer.

According to the subject-matter of the present invention, there is provided a method of manufacturing a battery cell as specified in claim <NUM>. The activation process can include charging the battery at less than <MAT> C rate and/or greater than <NUM> volts. The first current collector can be copper (Cu) and/or plated copper. The first current collector can be copper foil, stainless steel foil, titanium (Ti) foil, nickel (Ni) plated copper foil, aluminum (Al) plated copper foil, and/or titanium plated copper foil. The first current collector can have a thickness of <NUM> microns. The first electrode can be formed from a metal oxide, a metal fluoride, a metal sulfide, and/or a doped salt. The first electrode is formed from a lithium cobalt oxide (LiCoO<NUM>), lithium nickel cobalt oxide (LiNiCoO<NUM>), lithium manganese nickel cobalt oxide (LiNiMnCoO<NUM>), lithium manganese silicon oxide (Li<NUM>MnSiO<NUM>), lithium iron phosphate (LiFePO<NUM>), lithium fluoride (LiF), and/or lithium sulfide (Li<NUM>S). The metal extracted from the first electrode is lithium metal.

According to the invention, the protective layer is formed from a polymer. The protective layer can be formed from a crosslinked polymer and/or a non-crosslinked polymer. The protective layer is formed from a polymer composite that includes a plurality of different polymers. The polymer composite can further include one or more additives, the one or more additives comprising ceramic particles, metal salt particles, and metal stabilizers.

According to the invention, the battery further includes an electrolyte. The electrolyte is a liquid electrolyte, the liquid electrolyte including metal ions, and the liquid electrolyte further including one or more organic solvents. The metal ions can include lithium ions, and wherein the one or more organic solvents comprise ethylene carbonate ((CH<NUM>O)<NUM>CO) and/or lithium hexafluorophosphate (Li<NUM>PF<NUM>). The electrolyte can additionally comprise a solid-state electrolyte. The solid-state electrolyte can be a glass-ceramic binary sulfide electrolyte and/or a polymer electrolyte.

In some variations, the battery can further include a second current collector, the second current collector being coupled with the first electrode. The battery can further include a safety layer, the safety layer being deposited on the second current collector, and the safety layer being configured to respond to a temperature trigger and/or a voltage trigger.

According to the invention, the metal extracted from the first electrode and deposited between the first current collector and the protective layer can include dendrites. The protective layer is configured to prevent the dendrites from penetrating the separator and causing an internal short within the battery.

According to the invention, the activation process can cause a reduction at the first electrode, the reduction extracting metal from the first electrode, and the metal extracted from the first electrode being deposited between the first current collector and the protective layer to form the second electrode in situ between the first current collector and the protective layer.

Lithium metal may be an ideal material for battery electrodes (e.g., anodes) due to the very high specific capacity (e.g., approximately <NUM> mAh/g) of lithium metal. However, forming battery electrodes from lithium metal tends to be challenging in part because the low density of lithium metal renders the material especially fragile and difficult to handle during the production process. For instance, lithium has a density of approximately <NUM> grams per cubic centimeter (g/cm<NUM>) while copper has a density of approximately <NUM>/cm<NUM>. As such, a large amount of lithium metal may be required in producing lithium batteries. In particular, the lithium foil used to form battery electrodes is typically much thicker (e.g., more than <NUM> microns (µm)) than copper foil, which may be as thin as <NUM> microns. But including a large volume of lithium metal in a battery cell may incur unnecessary cost and compromise battery performance. For example, the positive electrode (e.g., cathode) in a battery may be unable to match the capacity of a negative electrode (e.g., anode) formed from a large amount of lithium metal. Here, an excess of lithium metal may occupy space within the battery cell without providing any additional capacity, thereby limiting the overall energy density of the battery cell. This excess lithium metal may further promote the formation of lithium dendrites within the battery cell (e.g., during charging of the battery cell). The presence of lithium dendrites within a battery cell may reduce the Coulombic efficiency as well as the cycle life of the battery cell. Moreover, the presence of lithium dendrites may further give rise to significant safety risks including, for example, internal shorts that may escalate into thermal runaway and explosions.

In some implementations of the current subject matter, a battery cell includes a current collector that is configured to enable an electrode (e.g., anode) to be formed from lithium metal in situ. For example, the current collector may be formed from copper (e.g., copper foil), plated copper (e.g., nickel plated copper foil, aluminum plated copper foil, and/or titanium plated copper foil), stainless steel (e.g., stainless steel foil), and/or titanium (e.g., titanium foil). According to some implementations of the current subject matter, the battery cell is subject to an activation process during which lithium metal is deposited on the surface of the current collector (e.g., the copper foil and/or the plated copper foil), thereby forming a lithium metal electrode (e.g., anode) in situ. For example, the cathode of the battery cell may be formed from a metal oxide (e.g., lithium cobalt oxide, lithium nickel cobalt oxide, lithium manganese nickel cobalt oxide), a doped salt (e.g., lithium iron phosphate), a metal fluoride (e.g., lithium fluoride (LiF)), a metal sulfide (e.g., lithium sulfide), and/or the like. The activation process includes charging the battery cell, thereby reducing the cathode of the battery cell. Metal that is extracted through the reduction of the cathode of the battery cell is deposited at the anode of the battery cell (e.g., on the surface of the current collector).

In some implementations of the current subject matter, a battery cell is subject to an activation process during which an electrode (e.g., anode) in the battery cell may be formed from lithium metal in situ. The lithium metal forming the electrode may be lithium dendrites, which may be filaments of lithium metal capable of penetrating a separator (e.g., between the anode and the cathode) in the battery cell and causing an internal short. As such, according to some implementations of the current subject matter, a current collector (e.g., the copper foil) is further coated with a protective layer, which may also be formed in situ. This protective layer formed from a polymer and/or a polymer composite. Meanwhile, the lithium metal (e.g., lithium dendrites) that is extracted from the lithium metal oxide at the cathode of the battery cell is deposited between the current collector (e.g., the copper foil) and the protective layer. The protective layer prevents internal shorts by at least preventing the lithium dendrites forming the anode of the battery cell from penetrating the separator between the anode and the cathode of the battery cell.

In some implementations of the current subject matter, a lithium metal electrode (e.g., anode) is formed in situ between a current collector (e.g., a copper foil and/or a plated copper foil) and a protective layer (e.g., a polymer and/or a polymer composite) of a battery cell. According to the invention, a lithium metal anode is formed by at least depositing, between the current collector and the protective layer, lithium metal extracted from a cathode of the battery cell during an activation process (e.g., charging of the battery cell). Forming the lithium metal electrode in situ obviates the highly inert environment required for manipulating highly reactive lithium metal (e.g., during lithium battery production). For instance, coating the surface of a lithium metal electrode with a protective layer (e.g., to prevent internal shorts) is typically performed in a dry room (e.g., with less than <NUM>% relative humidity) in order to prevent the lithium metal from reacting with moisture present in the air. By contrast, forming a lithium metal electrode in situ eliminates these costly limitations associated with conventional lithium battery production techniques. In fact, various implementations of the current subject matter obviate the handling of highly reactive lithium metal during the production of lithium batteries. Moreover, a sufficiently thin layer of lithium metal may be deposited between the current collector and the protective layer such that the capacity of the lithium metal anode matches that of the corresponding cathode and no excess lithium metal is present in the battery cell. Producing lithium batteries in this manner can be less costly while the resulting lithium batteries can exhibit optimal overall energy density.

For clarity and conciseness, various implementations of the current subject matter are described with respect to the production of lithium batteries having electrodes formed from lithium metal. However, it should be appreciated that various implementations of the current subject matter can also be applied to the production of other types of metal batteries including, for example, sodium (Na) batteries, potassium (K) batteries, and/or the like. Thus, the techniques disclosed herein may be used to form other metal electrodes in situ, thereby obviating the handling of reactive metals during the production of metal batteries.

<FIG> depicts a schematic diagram illustrating a battery cell <NUM> consistent with implementations of the current subject matter. Referring to <FIG>, the battery cell <NUM> may include a dual function current collector <NUM>, a protective layer <NUM>, a separator <NUM>, a first electrode <NUM>, and a current collector <NUM>.

In some implementations of the current subject matter, the dual function current collector <NUM> can be formed from copper (Cu) and/or plated copper. For example, the dual function collector <NUM> may be formed from copper foil, stainless steel foil, titanium foil, nickel (Ni) plated copper foil, aluminum (Al) plated copper foil, titanium (Ti) plated copper foil, and/or the like. The foil may have a thickness of approximately <NUM> microns. Meanwhile, the current collector <NUM> may be formed from aluminum (Al) (e.g., aluminum foil) and/or the like.

According to the invention, the protective layer <NUM> is formed from a polymer and/or a polymer composite. For instance, the protective layer <NUM> may be formed from a crosslinked polymer (e.g., containing crosslinking agents such as polyhedral oligomeric silsesquioxane (POSS), carboxymethyl cellulose (CMC), methacrylate, and/or the like), a non-crosslinked polymer, a stiff polymer (e.g., polyamide imide (PAI)), a block polymer, a composite of different polymers, and/or the like. Alternately and/or additionally, the protective layer <NUM> may be formed from a composite of one or more polymers and at least one additive including, for example, conductive and/or nonconductive ceramic particles, lithium salt particles (e.g., lithium fluoroborate (LiBF<NUM> and/or LiPF<NUM>), lithium nitrate (LiNO<NUM>), lithium bis(fluorosulfonyl)imide, and/or lithium bis(perfluoroethanesulfonyl)imide), lithium metal stabilizers (e.g., vinyl carbonate), and ether solvents, and/or the like. As shown in <FIG>, the protective layer <NUM> is applied directly to the surface of the dual function current collector <NUM>. According to some implementations not according to the invention, the protective layer <NUM> can be formed in situ.

According to the invention, the battery cell <NUM> is filled with a liquid electrolyte containing lithium ions. The liquid electrolyte may further contain one or more organic solvents including, for example, ethylene carbonate ((CH<NUM>O)<NUM>CO) and/or lithium hexafluorophosphate (Li<NUM>PF<NUM>). The protective layer <NUM> becomes ionically conductive by at least absorbing the liquid electrolyte. Additionally, the battery cell <NUM> may include a solid state electrolyte such as, for example, a lithium solid state electrolyte (e.g., lithium lanthanum titanates (LLTO), garnet-type zirconates (LLZO), lithium phosphate oxynitride (LiPON), glass-ceramics, binary lithium sulfide/diphosphorus pentasulfide (Li<NUM>S-P<NUM>S<NUM>), lithium oxides (Li<NUM>O-Al<NUM>O<NUM>-TiO<NUM>-P<NUM>O<NUM>)), and/or a polymer electrolyte.

In some implementations of the current subject matter, the separator <NUM> may be formed from a porous polyethylene film. The protective layer <NUM> can be configured to protect the separator <NUM> from being penetrated by lithium dendrites forming on the surface of the dual function current collector <NUM>, when the battery cell <NUM> is subject to an activation process (e.g., charging). Otherwise, an internal short can occur when lithium dendrites forming on the dual function current collector <NUM> penetrates the separator <NUM> to make contact with the first electrode <NUM>.

In some implementations of the current subject matter, the first electrode <NUM> may be formed from metal oxide, a metal fluoride, a metal sulfide, and/or a doped salt. According to the invention, the first electrode <NUM> is formed from lithium cobalt oxide (LiCoO<NUM>), lithium nickel cobalt oxide (LiNiCoO<NUM>), lithium manganese nickel cobalt oxide (LiNiMnCoO<NUM>), lithium manganese silicon oxide (Li<NUM>MnSiO<NUM>), lithium iron phosphate (LiFePO<NUM>), lithium sulfide (Li<NUM>S), and/or the like. The first electrode <NUM> may be the cathode (e.g., positive electrode) of the battery cell <NUM>. Here, <FIG> shows the battery cell <NUM> before the battery cell <NUM> is filled with an electrolyte and subject to an activation process (e.g., charging) to form a corresponding anode. However, it should be appreciated that lithium metal may be extracted from the first electrode <NUM> when the lithium metal oxide at the first electrode <NUM> is reduced during activation of the battery cell <NUM>. The lithium metal extracted from the first electrode <NUM> is deposited between the dual function current collector <NUM> and the protective layer <NUM>, thereby forming a lithium metal anode in situ (not shown in <FIG>).

<FIG> depicts a schematic diagram illustrating the battery cell <NUM> consistent with implementations of the current subject matter. Referring to <FIG>, the battery cell <NUM> may include a safety layer <NUM> in addition to the dual function current collector <NUM>, the protective layer <NUM>, the separator <NUM>, the first electrode <NUM>, the first safety layer <NUM>, and the current collector <NUM>. As shown in <FIG>, the safety layer <NUM> may be disposed between the current collector <NUM> and the electrode <NUM>. The safety layer <NUM> may be formed from a mixture including lithium carbonate, calcium carbonate, conductive additives (e.g., carbon black), and/or binders (e.g., cross linked and/or non cross-linked binders). It should be appreciated that the safety layer <NUM> can be configured to respond to one or more temperature and/or voltage triggers (e.g., an excessively high temperature and/or voltage).

<FIG> depicts a schematic diagram illustrating the battery cell <NUM> consistent with implementations of the current subject matter. As shown in <FIG>, the battery cell <NUM> is with a liquid electrolyte <NUM>, which can include lithium ions. The liquid electrolyte <NUM> can further contain organic solvents such as, for example, ethylene carbonate ((CH<NUM>O)<NUM>CO), dimethyl carbonate (DMC), <NUM>,<NUM>-dimethoxyethane, and/or lithium hexafluorophosphate (LiPF<NUM>). In some implementations of the current subject matter, the liquid electrolyte <NUM> may saturate the protective layer <NUM>, the separator <NUM>, and/or the first electrode <NUM>. In particular, the liquid electrolyte <NUM> is absorbed by the polymer contained within the protective layer <NUM>, thereby rendering the protective layer <NUM> and the separator <NUM> ionically conductive.

<FIG> depicts a schematic diagram illustrating the battery cell <NUM> consistent with implementations of the current subject matter. As shown in <FIG>, the battery cell <NUM> (e.g., filled with the liquid electrolyte <NUM>) is subject to an activation process in order to form a second electrode <NUM> in situ. According to the invention, the battery cell <NUM> is charged, thereby extracting lithium metal from the first electrode <NUM> by at least reducing the lithium metal oxide at the first electrode <NUM>. The lithium metal extracted from the first electrode <NUM> is deposited between the protective layer <NUM> and the dual function current collector <NUM>. This lithium metal forms the second electrode <NUM>, which may serve as the cathode of the battery cell <NUM>.

<FIG> depicts a schematic diagram illustrating the battery cell <NUM>. Referring to <FIG>, the battery cell <NUM> can include a solid state electrolyte <NUM> instead of (not according to the invention) or in addition to (according to the invention) the liquid electrolyte <NUM>. In some implementations of the current subject matter, the solid state electrolyte <NUM> can be a lithium solid state electrolyte (e.g., lithium lanthanum titanates (LLTO), garnet-type zirconates (LLZO), lithium phosphate oxynitride (LiPON), glass-ceramics, binary lithium sulfide/diphosphorus pentasulfide (Li<NUM>S-P<NUM>S<NUM>), lithium oxides (Li<NUM>O-Al<NUM>O<NUM>-TiO<NUM>-P<NUM>O<NUM>)). Alternately and/or additionally, the solid state electrolyte <NUM> can be a polymer electrolyte, which may contain one or more crosslinking agents such as, for example, polyhedral oligomeric silsesquioxane (POSS), carboxymethyl cellulose (CMC), and/or the like. The solid state electrolyte <NUM> can be deposited on top the protective layer <NUM>. According to the invention, the battery cell <NUM> is subject to an activation process (e.g., charging) during which lithium metal is extracted from the first electrode <NUM> (e.g., cathode). This lithium metal is deposited between the dual function current collector <NUM> and the protective layer <NUM>, thereby forming the second electrode <NUM> in situ.

<FIG> depicts a schematic diagram illustrating the battery cell <NUM> consistent with implementations of the current subject matter. Referring to <FIG>, the battery cell <NUM> can include the solid state electrolyte <NUM> (e.g., instead of and/or in addition to the liquid electrolyte <NUM>) and an additional protective layer <NUM> deposited on top of the solid state electrolyte <NUM>. The additional protective layer <NUM> can be formed from a polymer and/or a polymer composite. For instance, the additional protective layer <NUM> may be formed from a crosslinked polymer (e.g., containing crosslinking agents such as polyhedral oligomeric silsesquioxane (POSS), carboxymethyl cellulose (CMC), and/or the like), a non-crosslinked polymer, a stiff polymer (e.g., polyamide imide (PAI)), a block polymer, and/or a composite of different polymers. Alternately and/or additionally, the additional protective layer <NUM> may be formed from a composite of one or more polymers and at least one additive including, for example, conductive and/or nonconductive ceramic particles, lithium salt particles (e.g., LiPF<NUM> and/or LiPF<NUM>), lithium metal stabilizers, and/or the like.

In some implementations of the current subject matter, the battery cell <NUM> is subject to an activation process (e.g., charging) during which lithium metal is extracted from the first electrode <NUM> (e.g., cathode). This lithium metal is deposited between the dual function current collector <NUM> and the protective layer <NUM>, thereby forming the second electrode <NUM> in situ. The lithium metal forming the second electrode <NUM> are lithium dendrites, which are capable of penetrating the separator <NUM> and giving rise to internal shorts. As such, the presence of the protective layer <NUM>, the solid state electrolyte <NUM>, and/or the additional protective layer <NUM> may prevent the lithium dendrites from penetrating the separator <NUM> and causing an internal short. Furthermore, the protective layer <NUM> and the additional protective layer <NUM> can also prevent the solid state electrolyte <NUM> from coming in contact with both the first electrode <NUM> and/or the second electrode <NUM>, thereby thwarting any potential interface reaction between the solid state electrolyte <NUM> and the first electrode <NUM> and/or the second electrode <NUM>.

<FIG> depicts a flowchart illustrating a process <NUM> for forming a lithium metal electrode in situ consistent with implementations of the current subject matter. Referring to <FIG>, the process <NUM> may be performed to form the second electrode <NUM> in the battery cell <NUM>.

The battery cell <NUM> is formed to include the dual function current collector <NUM> and the protective layer <NUM> (<NUM>). According to the invention, the battery cell <NUM> includes the dual function current collector <NUM>, which can be formed from copper (Cu) foil and/or plated copper foil (e.g., aluminum (Al) plated copper foil, nickel (Ni) plated copper foil, titanium (Ti) plated copper foil, and/or the like). The battery cell <NUM> further includes the protective layer <NUM>, which may be formed from a crosslinked polymer (e.g., containing crosslinking agents such as polyhedral oligomeric silsesquioxane (POSS), carboxymethyl cellulose (CMC), and/or the like), a non-crosslinked polymer, a stiff polymer (e.g., polyamide imide (PAI)), a block polymer, and/or a composite of different polymers. According to the invention, the protective layer <NUM> is formed from a composite of one or more polymers and it may further include at least one additive including, for example, conductive and/or nonconductive ceramic particles, lithium salt particles (e.g., LiPF<NUM> and/or LiPF<NUM>), lithium metal stabilizers, and/or the like.

In some implementations of the current subject matter, the battery cell <NUM> further includes the first electrode <NUM>, which may serve as the cathode of the battery cell <NUM>. The first electrode <NUM> is formed from a lithium metal oxide (e.g., lithium cobalt oxide (LiCoO<NUM>), lithium nickel cobalt oxide (LiNiCoO<NUM>), lithium manganese nickel cobalt oxide (LiNiMnCoO<NUM>)). As shown in <FIG>, the battery cell <NUM> includes the liquid electrolyte <NUM> and can additionally include a solid state electrolyte <NUM>. includes the current collector <NUM>, which may be formed from aluminum (Al) foil and/or the like.

The battery cell <NUM> is subject to an activation process to at least form a lithium metal electrode in situ (<NUM>). For example, the battery cell <NUM> can be charged at a low rate (e.g., <MAT> rate and/or <NUM> hours charging to its fully charged state) and a high voltage (e.g., > <NUM> volts). Charging the battery cell <NUM> in this manner causes the lithium metal oxide at the first electrode <NUM> to reduce, thereby extracting lithium metal from the first electrode <NUM>. This lithium metal is deposited between the dual function current collector <NUM> and the protective layer <NUM>, thereby forming the second electrode <NUM> in situ. This second electrode <NUM> may serve as the anode of the battery cell <NUM>. As noted above, the lithium metal deposited on the dual function current collector <NUM> to form the second electrode <NUM> are lithium dendrites that are capable of penetrating the separator <NUM> to cause an internal short. As such, the battery cell <NUM> includes the protective layer <NUM> to prevent the lithium dendrites from penetrating the separator <NUM> and causing an internal short.

<FIG> depicts a flowchart illustrating a process <NUM> for forming a protective layer consistent with some implementations of the current subject matter. Referring to <FIG>, the process <NUM> may be performed to form the protective layer <NUM>. For instance, the process <NUM> can be performed to form protective layer <NUM> from any polymer, such as, for example, a crosslinked polymer (e.g., containing crosslinking agents such as polyhedral oligomeric silsesquioxane (POSS), carboxymethyl cellulose (CMC), and/or the like), a non-crosslinked polymer, a stiff polymer (e.g., polyamide imide (PAI)), a block polymer, a composite of different polymers, and/or the like. Alternately and/or additionally, the process <NUM> can be performed to form the protective layer <NUM> from any combination of polymers and additives including, for example, conductive and/or nonconductive ceramic particles, lithium salt particles (e.g., LiPF<NUM> and/or LiPF<NUM>), lithium metal stabilizers, and/or the like.

As shown in <FIG>, a binder solution can be formed by at least dissolving a binder into a solvent (<NUM>). A slurry can be formed by adding, to the binder solution, one or more conductive additives, ceramic powders, and/or dielectric material (<NUM>). It should be appreciated that operation <NUM> may be optional.

The surface of a dual function current collector can be coated with the slurry (<NUM>). For example, the slurry can be used to coat the surface of the dual function current collector <NUM>, which may be formed from copper (Cu) foil and/or coated copper foil. A protective layer can be formed on the surface of the dual function current collector by at least drying the slurry (<NUM>). For instance, drying the slurry can form the protective layer <NUM> on the surface of the dual function current collector <NUM>. It should be appreciated that the protective layer <NUM>, the solid state electrolyte <NUM>, and/or the additional protective layer <NUM> shown in <FIG> can be coated onto the copper foil surface at once by a slot die coating system configured with a slot die with three outputs.

In some implementations of the current subject matter, the protective layer can be further subject to thermal treatment and/or light treatment (<NUM>). For example, the protective layer <NUM> may be formed from a crosslinked polymer containing, for example, crosslinking agents such as polyhedral oligomeric silsesquioxane (POSS), carboxymethyl cellulose (CMC), and/or the like. As such, the protective layer <NUM> may be subject to thermal treatment and/or ultraviolet (UV) light treatment.

<FIG> depicts a flowchart illustrating a process <NUM> for forming a cathode consistent with some implementations of the current subject matter. Referring to <FIG> and <FIG>, the process <NUM> can be performed to form the first electrode <NUM>. For instance, the process <NUM> can be performed to form the first electrode <NUM> from any metal oxide including, for example, a lithium metal oxide such as lithium cobalt oxide (LiCoO<NUM>), lithium nickel cobalt oxide (LiNiCoO<NUM>), lithium manganese nickel cobalt oxide (LiNiMnCoO<NUM>), lithium iron phosphate (LiFePO<NUM>), lithium sulfide (Li<NUM>S), and/or the like.

As shown in <FIG>, a binder solution can be formed by at least dissolving a binder into a solvent (<NUM>). A first slurry can be formed by adding, to the binder solution, one or more conductive additives (<NUM>). A second slurry can be formed by adding, to the first slurry, cathode material (<NUM>). The surface of a current collector can be coated with the second slurry (<NUM>). For example, the second slurry (e.g., the electrode slurry) can be used to coat the surface of the current collector <NUM>, thereby forming the first electrode <NUM> directly on the surface of the current collector <NUM>. The electrode can be compressed to a specific thickness (<NUM>). For instance, the first electrode <NUM> can be compressed to a thickness that conforms to the dimensional and/or performance specifications of the battery cell <NUM>.

<FIG> depicts a flowchart illustrating a process <NUM> for assembling a battery cell consistent with implementations of the current subject matter. Referring to <FIG> and <FIG>, the process <NUM> can be performed to assemble the battery cell <NUM>. For example, the process <NUM> can be performed to assemble, into the battery cell <NUM>, the dual function current collector <NUM>, the protective layer <NUM>, the separator <NUM>, the first electrode <NUM>, and the current collector <NUM>. It should be appreciated that the process <NUM>, the process <NUM>, and/or the process <NUM> may implement operation <NUM> of the process <NUM>.

As shown in <FIG>, a cathode can be dried (<NUM>). For example, the first electrode <NUM> (e.g., metal oxide formed on top of the current collector <NUM> by the process <NUM>) can be dried at <NUM> for <NUM> hours. A dual function current collector and protective layer can be dried (<NUM>). For instance, the dual function current collector <NUM> (e.g., copper foil and/or copper plated foil) and the protective layer <NUM> (e.g., polymer and/or polymer composite), both of which may be formed by performing the process <NUM>, can also be dried at <NUM> for <NUM> hours. The cathode, the dual function collector, and the protective layer can be punched into pieces with an electrode tab (<NUM>).

In some implementations of the current subject matter, a jelly roll can be formed by laminating the cathode with a separator, the protective layer, and the dual function current collector (<NUM>). For instance, the first electrode <NUM> can be laminated first with the separator <NUM> (e.g., porous polyethylene) followed by the protective layer <NUM> and the dual function current collector <NUM>. The jelly roll can be inserted into a battery cell casing (<NUM>). For example, the resulting jelly roll can be inserted into a composite bag formed from, for example, aluminum (Al). As used herein, jelly roll may refer to a structure formed by at least layering, for example, the cathode, the separator, the protective layer, and the dual function current collector.

According to the invention, the battery cell casing is filled with an electrolyte (<NUM>). For instance, the battery cell <NUM> can be filled with the liquid electrolyte <NUM>, which can saturate at least the protective layer <NUM>, the separator <NUM>, and/or the first electrode <NUM>. The liquid electrolyte <NUM> may contain metal ions such as, for example, lithium ions. Thus, filling the battery cell <NUM> with the liquid electrolyte <NUM> renders the protective layer <NUM> and the separator <NUM> ionically conductive. The battery cell casing can be sealed (<NUM>) and the battery cell can be aged (<NUM>). For example, the battery cell <NUM> can be sealed and aged for <NUM> hours. The aged battery cell <NUM> is subsequently subject to an activation process (e.g., operation <NUM> of the process <NUM>), during which the battery cell <NUM> can be charged at a low rate (e.g., <MAT> rate or charging to its fully charged state in ten hours) and a high voltage (e.g., > <NUM> volts). The aged battery cell <NUM> is activated in this manner to at least form, in situ, the second electrode <NUM> (e.g., anode) from lithium metal extracted from the first electrode <NUM>.

The following sample cells, sample lithium composite films, and sample protective layers are provided for illustrative purposes only. It should be appreciated that different cells, lithium composite films, and protective layers may be formed in accordance with the present disclosure.

In some implementations of the current subject matter, the dual function current collector <NUM> is formed without the protective layer <NUM>. For instance, copper (Cu) foil having a thickness of <NUM> microns is used to form the dual function current collector <NUM> without the protective layer <NUM>.

In some implementations of the current subject matter, the first electrode <NUM> (e.g., cathode) is formed on top of the current collector <NUM> by at least performing the process <NUM>. For instance, the first electrode <NUM> is formed from a lithium nickel manganese cobalt oxide (LiNi<NUM>Mn<NUM>Co<NUM>O<NUM>). Here, <NUM> grams of a polyvinylidene fluoride (PVDF) binder and <NUM> grams of a binder BM700 (e.g., manufactured by from Zeon Corporation of Tokyo, Japan) is dissolved into <NUM> grams of N-methylpyrrolidone (NMP) to form a binder solution. Thereafter, <NUM> grams of carbon black and <NUM> grams of graphite is added to this binder solution and mixed for <NUM> minutes at <NUM> revolutions per minute to form a first slurry. A flowable second slurry can then be formed by adding <NUM> grams of lithium nickel manganese cobalt oxide (LiNi<NUM>Mn<NUM>Co<NUM>O<NUM>) to this first slurry and mixing for <NUM> minutes at <NUM> revolutions per minute. Here, additional amounts of N-methylpyrrolidone may be added to adjust the viscosity of the second slurry. The resulting second slurry (e.g., electrode slurry) is coated onto the current collector <NUM>, which may be aluminum (Al) foil having a thickness of <NUM> microns. The coating may be performed using an automatic coating machine with the first heat zone set to approximately <NUM> and the second heat zone set to approximately <NUM> to remove the liquid solvent (e.g., N-methylpyrrolidone) present in the second slurry. When dried, the first electrode <NUM> and the current collector <NUM> can have a combined thickness of approximately <NUM> microns.

In some implementations of the current subject matter, the first electrode <NUM> is coated with an additional layer containing polyvinylidene fluoride LBG-<NUM> from Arkema Inc. Thus, a third slurry is formed by mixing <NUM> grams of polyvinylidene fluoride and <NUM> grams of a silicon dioxide (SiO<NUM>) nano powder into <NUM> grams of N-methylpyrrolidone, and mixing for <NUM> minutes at <NUM> revolutions per minute. The first electrode <NUM> is coated with a <NUM> micron thick layer of this third slurry. Once dried, the first electrode <NUM> is compressed to a thickness of approximately <NUM> microns.

The dual function current collector <NUM> and the first electrode <NUM> is punched into pieces using an electrode tab that measures approximately <NUM> centimeters wide and <NUM> centimeter long. For example, the dual function current collector <NUM> (e.g., copper foil) is punched into pieces measuring <NUM> centimeters in length and <NUM> centimeters in width. Meanwhile, the first electrode <NUM> is punched into pieces measuring <NUM> centimeters in length and <NUM> centimeters in width. Both the dual function current collector <NUM> and the first electrode <NUM> is dried at <NUM> for <NUM> hours. A jelly roll is formed by laminating the dual function current collector <NUM>, the first electrode <NUM>, and the current collector <NUM> on opposite sides of the separator <NUM>, which may be approximately <NUM> microns thick. As such, the resulting jelly roll may have the dual function current collector <NUM> on one side of the separator <NUM> while the first electrode <NUM> and the current collector <NUM> may be on the opposite side of the separator <NUM>.

In some implementations of the current subject matter, the jelly roll is inserted into an aluminum composite bag, which has been dried in a vacuum oven set to <NUM> for <NUM> hrs. The aluminum composite bag can then be filled with an organic carbonate based liquid electrolyte containing lithium hexafluorophosphate (LiPF<NUM>) before the aluminum composite bag is sealed, at <NUM>, to form the battery cell <NUM>. The sealed aluminum composite bag is allowed to rest for <NUM> hours before being charged, at room temperature, to <NUM>. 6V at a rate of <MAT> C rate or <NUM> hours to its fully charged state. The battery cell <NUM> is allowed to rest for <NUM> additional days at which point the battery cell <NUM> is punctured, under vacuum, to release any gases before being resealed. According to some implementations of the current subject matter, the resulting battery cell <NUM> can serve as a control sample.

<FIG> depicts a line graph <NUM> illustrating a charge profile and a discharge profile of the battery cell <NUM> consistent with implementations of the current subject matter. Referring to <FIG>, the line graph <NUM> illustrates the capacity of the battery cell <NUM> relative to the charge voltage and the discharge voltage of the battery cell <NUM>, as measured at room temperature. As shown in <FIG>, when the battery cell <NUM> is configured as a control sample having no protective layer on the surface of the copper foil current collector, the ratio of discharge capacity relative to charge capacity is approximately <NUM>%.

In some implementations of the current subject matter, the protective layer <NUM> is formed on the surface of the dual function current collector <NUM> by at least performing the process <NUM>. For instance, the protective layer <NUM> is formed from polyethylene oxide (PEO) while the dual function current collector <NUM> is formed from copper (Cu) foil. As such, a binder solution is formed by dissolving the <NUM> grams of polyethylene oxide binder into <NUM> grams of water. Thereafter, <NUM> grams of carbon black (e.g., Super-P) is added into the binder solution and mixed for <NUM> minutes at <NUM> revolutions per minute (RPM) to from a slurry. Here, <NUM> grams of styrene butadiene rubber (SBR) is further added to the slurry and mixed for <NUM> minutes at <NUM> revolutions per minute. This resulting slurry is coated onto the surface of copper (Cu) foil having a thickness of <NUM> microns. The coating is performed using an automatic coating machine with the first heat zone set to approximately <NUM> and the second heat zone set to approximately <NUM> to remove the water present in the slurry. When dried, the protective layer <NUM> can have an average thickness of approximately <NUM>-<NUM> microns.

In some implementations of the current subject matter, the first electrode <NUM> (e.g., cathode) is formed on top of the current collector <NUM> by at least performing the process <NUM>. For instance, the first electrode <NUM> is formed from a lithium nickel manganese cobalt oxide (LiNi<NUM>Mn<NUM>Co<NUM>O<NUM>). Here, <NUM> grams of a polyvinylidene fluoride (PVDF) binder is dissolved into <NUM> grams of N-methylpyrrolidone (NMP) and mixed for <NUM> minutes at <NUM> revolutions per minute to form a binder solution. Thereafter, <NUM> grams of graphite is added to this binder solution and mixed for <NUM> minutes at <NUM> revolutions per minute to form a first slurry. A flowable second slurry can then be formed by adding <NUM> grams of lithium nickel manganese cobalt oxide (LiNi<NUM>Mn<NUM>Co<NUM>O<NUM>) to this first slurry and mixing for <NUM> minutes at <NUM> revolutions per minute. Here, additional amounts of N-methylpyrrolidone may be added to adjust the viscosity of the second slurry. The resulting second slurry (e.g., electrode slurry) is coated onto the current collector <NUM>, which may be aluminum (Al) foil having a thickness of <NUM> microns. The coating may be performed using an automatic coating machine with the first heat zone set to approximately <NUM> and the second heat zone set to approximately <NUM> to remove the N-methylpyrrolidone present in the second slurry. When dried, the first electrode <NUM> and the current collector <NUM> can have a combined thickness of approximately <NUM> microns, which is further compressed to a thickness of approximately <NUM> microns.

In some implementations of the current subject matter, the battery cell <NUM> is formed by performing the process <NUM>. Thus, forming the battery cell <NUM> can include drying the dual function current collector <NUM>, the protective layer <NUM>, and the first electrode <NUM> at <NUM> for <NUM> hours. The dual function current collector <NUM>, the protective layer <NUM>, and the first electrode <NUM> is further punched into pieces using an electrode tab. A jelly roll is formed from the dual function current collector <NUM>, the protective layer <NUM>, the separator <NUM>, the first electrode <NUM>, and the current collector <NUM>. For instance, the dual function current collector <NUM>, the protective layer <NUM>, the separator <NUM>, the first electrode <NUM>, and the current collector <NUM> is laminated such that the dual function current collector <NUM> and the protective layer <NUM> are on one side of the separator <NUM> while the first electrode <NUM> and the current collector <NUM> are on the opposite side of the separator <NUM>. Here, the separator <NUM> can have a thickness of approximately <NUM> microns.

This jelly roll is inserted flat into an aluminum (Al) composite bag that has been dried for <NUM> hours in a vacuum oven set to <NUM>. The aluminum composite bag is filled with an organic carbonate based liquid electrolyte containing lithium hexafluorophosphate (LiPF<NUM>) before the aluminum composite bag is sealed to form the battery cell <NUM>. The battery cell <NUM> may be allowed to rest for approximately <NUM> hours before being subject to an activation process that includes charging, at room temperature, the battery cell <NUM> to <NUM> volts at a rate of <MAT> rate. The activated battery cell <NUM> is allowed to rest for <NUM> additional days at which point the battery cell <NUM> is punctured, under vacuum, to release any gases before being resealed.

In some implementations of the current subject matter, the protective layer <NUM> is formed on the surface of the dual function current collector <NUM> by at least performing the process <NUM>. For instance, the protective layer <NUM> is formed from polyethylene oxide (PEO) while the dual function current collector <NUM> is formed from copper (Cu) foil. As such, a binder solution is formed by dissolving the <NUM> grams of polyethylene oxide binder into <NUM> grams of deionized water and mixing for <NUM> minutes at <NUM> revolutions per minute (RPM) to from a slurry. This slurry is coated onto the surface of copper (Cu) foil having a thickness of <NUM> microns. The coating is performed using an automatic coating machine with the first heat zone set to approximately <NUM> and the second heat zone set to approximately <NUM> to remove the water present in the slurry. When dried, the protective layer <NUM> can have an average thickness of approximately <NUM>-<NUM> microns.

<FIG> depicts a line graph <NUM> illustrating a charge profile and a discharge profile of the battery cell <NUM> consistent with implementations of the current subject matter. Referring to <FIG>, the line graph <NUM> illustrates the capacity of the battery cell <NUM> relative to the charge voltage and the discharge voltage of the battery cell <NUM>, as measured at room temperature. As shown in <FIG>, when the battery cell <NUM> is configured as the sample cell <NUM>, the ratio of discharge capacity relative to charge capacity is approximately <NUM>%.

In some implementations of the current subject matter, the protective layer <NUM> is formed on the surface of the dual function current collector <NUM> by at least performing the process <NUM>. For instance, the protective layer <NUM> is formed from polyethylene oxide (PEO) while the dual function current collector <NUM> is formed from copper (Cu) foil. As such, a binder solution is formed by dissolving the <NUM> grams of polyethylene oxide binder into <NUM> grams of deionized water and mixing for <NUM> minutes at <NUM> revolutions per minute (RPM) to from a slurry. This slurry is coated onto the surface of copper (Cu) foil having a thickness of <NUM> microns. The coating is performed using an automatic coating machine with the first heat zone set to approximately <NUM> and the second heat zone set to approximately <NUM> to remove the deionized water present in the slurry. When dried, the protective layer <NUM> can have an average thickness of approximately <NUM>-<NUM> microns.

In some implementations of the current subject matter, the first electrode <NUM> (e.g., cathode) is formed on top of the current collector <NUM> by at least performing the process <NUM>. For instance, the first electrode <NUM> is formed from a lithium nickel manganese cobalt oxide (LiNi<NUM>Mn<NUM>Co<NUM>O<NUM>). Here, <NUM> grams of a polyvinylidene fluoride (PVDF) binder having a high molecular weight and <NUM> grams of carbon is dissolved into <NUM> grams of N-methylpyrrolidone (NMP) and mixed for <NUM> minutes at <NUM> revolutions per minute to form a binder solution. Thereafter, <NUM> grams of graphite is added to this binder solution and mixed for <NUM> minutes at <NUM> revolutions per minute to form a first slurry. A flowable second slurry can then be formed by adding <NUM> grams of lithium nickel manganese cobalt oxide (LiNi<NUM>Mn<NUM>Co<NUM>O<NUM>) to this first slurry and mixing for <NUM> minutes at <NUM> revolutions per minute. Here, additional amounts of N-methylpyrrolidone may be added to adjust the viscosity of the second slurry. The resulting second slurry (e.g., electrode slurry) is coated onto the current collector <NUM>, which may be aluminum (Al) foil having a thickness of <NUM> microns. The coating may be performed using an automatic coating machine with the first heat zone set to approximately <NUM> and the second heat zone set to approximately <NUM> to remove the N-methylpyrrolidone present in the second slurry. When dried, the first electrode <NUM> and the current collector <NUM> can have a combined thickness of approximately <NUM> microns, which is further compressed to a thickness of approximately <NUM> microns.

<FIG> depicts a line graph <NUM> illustrating a charge profile and a discharge profile of the battery cell <NUM> consistent with implementations of the current subject matter. Referring to <FIG>, the line graph <NUM> illustrates the capacity of the battery cell <NUM> relative to the charge voltage and the discharge voltage of the battery cell <NUM>, as measured at room temperature. As shown in <FIG>, when the battery cell <NUM> is configured as the sample cell <NUM>, the ratio of discharge capacity relative to charge capacity is approximately <NUM>%. It should be appreciated that the discharge of the battery cell <NUM> is suspended at approximately <NUM> ampere-hour, thereby causing the voltage dip observed at around <NUM> ampere-hour.

In some implementations of the current subject matter, the protective layer <NUM> is formed on the surface of the dual function current collector <NUM> by at least performing the process <NUM>. For instance, the protective layer <NUM> is formed from polyvinylidene fluoride (PVDF LBG-<NUM>) (e.g., manufactured by Arkema Inc. of King of Prussia, PA) while the dual function current collector <NUM> is formed from copper (Cu) foil. As such, a binder solution is formed by dissolving the <NUM> grams of the polyvinylidene fluoride binder into <NUM> grams of N-methylpyrrolidone (NMP) and mixing for <NUM> minutes at <NUM> revolutions per minute (RPM) to from a slurry. This slurry is coated onto the surface of copper (Cu) foil having a thickness of <NUM> microns. The coating is performed using an automatic coating machine with the first heat zone set to approximately <NUM> and the second heat zone set to approximately <NUM> to remove the N-methylpyrrolidone present in the slurry. When dried, the protective layer <NUM> can have an average thickness of approximately <NUM>-<NUM> microns.

In some implementations of the current subject matter, the first electrode <NUM> (e.g., cathode) is formed on top of the current collector <NUM> by at least performing the process <NUM>. For instance, the first electrode <NUM> is formed from a lithium nickel manganese cobalt oxide (LiNi<NUM>Mn<NUM>Co<NUM>O<NUM>). Here, <NUM> grams of a high molecular weight polyvinylidene fluoride (PVDF (high molecular weight)) binder and <NUM> grams of carbon is dissolved into <NUM> grams of N-methylpyrrolidone (NMP) and mixed for <NUM> minutes at <NUM> revolutions per minute to form a binder solution. Thereafter, <NUM> grams of graphite is added to this binder solution and mixed for <NUM> minutes at <NUM> revolutions per minute to form a first slurry. A flowable second slurry can then be formed by adding <NUM> grams of lithium nickel manganese cobalt oxide (LiNi<NUM>Mn<NUM>Co<NUM>O<NUM>) to this first slurry and mixing for <NUM> minutes at <NUM> revolutions per minute. Here, additional amounts of N-methylpyrrolidone may be added to adjust the viscosity of the second slurry. The resulting second slurry (e.g., electrode slurry) is coated onto the current collector <NUM>, which may be aluminum (Al) foil having a thickness of <NUM> microns. The coating may be performed using an automatic coating machine with the first heat zone set to approximately <NUM> and the second heat zone set to approximately <NUM> to remove the N-methylpyrrolidone present in the second slurry. When dried, the first electrode <NUM> and the current collector <NUM> can have a combined thickness of approximately <NUM> microns, which is further compressed to a thickness of approximately <NUM> microns.

In some implementations of the current subject matter, the first electrode <NUM> (e.g., cathode) is formed on top of the current collector <NUM> by at least performing the process <NUM>. For instance, the first electrode <NUM> is formed from a lithium nickel manganese cobalt oxide (LiNi<NUM>Mn<NUM>Co<NUM>O<NUM>). Here, <NUM> grams of a high molecular weight polyvinylidene fluoride (PVDF (high molecular weight)), <NUM> grams of BM700 (e.g., manufactured by Zeon Corporation of Tokyo Japan) dissolved in <NUM> grams of N-methylpyrrolidone (NMP), and <NUM> grams of carbon black is dissolved into <NUM> grams of N-methylpyrrolidone and mixed for <NUM> minutes at <NUM> revolutions per minute to form a binder solution. Thereafter, <NUM> grams of graphite is added to this binder solution and mixed for <NUM> minutes at <NUM> revolutions per minute to form a first slurry. A flowable second slurry can then be formed by adding <NUM> grams of lithium nickel manganese cobalt oxide (LiNi<NUM>Mn<NUM>Co<NUM>O<NUM>) (NMC433) to this first slurry and mixing for <NUM> minutes at <NUM> revolutions per minute. Here, additional amounts of N-methylpyrrolidone may be added to adjust the viscosity of the second slurry. The resulting second slurry (e.g., electrode slurry) is coated onto the current collector <NUM>, which may be aluminum (Al) foil having a thickness of <NUM> microns. The coating may be performed using an automatic coating machine with the first heat zone set to approximately <NUM> and the second heat zone set to approximately <NUM> to remove the N-methylpyrrolidone present in the second slurry. When dried, the first electrode <NUM> and the current collector <NUM> can have a combined thickness of approximately <NUM> microns, which is further compressed to a thickness of approximately <NUM> microns.

<FIG> depicts a scatter plot <NUM> illustrating a cycle life performance of the battery cell <NUM> consistent with implementations of the current subject matter. Referring to <FIG>, the scatter plot <NUM> illustrates the cycle life of the battery cell <NUM> (e.g., measured in the number of complete charge and discharge cycles supported by the battery cell <NUM> prior to depletion) relative to the capacity of the battery cell <NUM>, when the battery cell is configured as the sample cell <NUM>.

In some implementations of the current subject matter, the protective layer <NUM> is formed on the surface of the dual function current collector <NUM> by at least performing the process <NUM>. For instance, the protective layer <NUM> is formed from polyethylene oxide (PEO) and the crosslinking agent carboxymethyl cellulose (CMC) while the dual function current collector <NUM> is formed from copper (Cu) foil. As such, a binder solution is formed by dissolving the <NUM> grams of polyethylene oxide and <NUM> grams of carboxymethyl cellulose into <NUM> grams of deionized water. The resulting mixture may be mixed for <NUM> minutes at <NUM> revolutions per minute (RPM) to from a slurry. This slurry can then be coated onto the surface of copper (Cu) foil having a thickness of <NUM> microns. The coating is performed using an automatic coating machine with the first heat zone set to approximately <NUM> and the second heat zone set to approximately <NUM> to remove the deionized water present in the slurry. When dried, the protective layer <NUM> can have an average thickness of approximately <NUM>-<NUM> microns.

In some implementations of the current subject matter, the first electrode <NUM> (e.g., cathode) is formed on top of the current collector <NUM> by at least performing the process <NUM>. For instance, the first electrode <NUM> is formed from a lithium nickel manganese cobalt oxide (LiNi<NUM>Mn<NUM>Co<NUM>O<NUM>). Here, <NUM> grams of a high molecular weight polyvinylidene fluoride (PVDF (high molecular weight), <NUM> grams of BM700 (e.g., manufactured by Zeon Corporation of Tokyo, Japan) dissolved in <NUM> grams of N-methylpyrrolidone (NMP), and <NUM> grams of carbon black is dissolved into <NUM> grams of N-methylpyrrolidone and mixed for <NUM> minutes at <NUM> revolutions per minute to form a binder solution. Thereafter, <NUM> grams of graphite is added to this binder solution and mixed for <NUM> minutes at <NUM> revolutions per minute to form a first slurry. A flowable second slurry can then be formed by adding <NUM> grams of lithium nickel manganese cobalt oxide (LiNi<NUM>Mn<NUM>Co<NUM>O<NUM>) (NMC433) to this first slurry and mixing for <NUM> minutes at <NUM> revolutions per minute. Here, additional amounts of N-methylpyrrolidone may be added to adjust the viscosity of the second slurry. The resulting second slurry (e.g., electrode slurry) is coated onto the current collector <NUM>, which may be aluminum (Al) foil having a thickness of <NUM> microns. The coating may be performed using an automatic coating machine with the first heat zone set to approximately <NUM> and the second heat zone set to approximately <NUM> to remove the N-methylpyrrolidone present in the second slurry. When dried, the first electrode <NUM> and the current collector <NUM> can have a combined thickness of approximately <NUM> microns, which is further compressed to a thickness of approximately <NUM> microns.

In some implementations of the current subject matter, the battery cell <NUM> is formed by performing the process <NUM>. Thus, forming the battery cell <NUM> can include drying the dual function current collector <NUM>, the protective layer <NUM>, and the first electrode <NUM> at <NUM> for <NUM> hours. The dual function current collector <NUM>, the protective layer <NUM>, and the first electrode <NUM> is further punched into pieces using an electrode tab. A jelly roll is formed from the dual function current collector <NUM>, the protective layer <NUM>, the separator <NUM>, the first electrode <NUM>, and the current collector <NUM>. For instance, the dual function current collector <NUM>, the protective layer <NUM>, the separator <NUM>, the first electrode <NUM>, and the current collector <NUM> is laminated such that the dual function current collector <NUM> and the protective layer <NUM> are on one side of the separator <NUM> while the first electrode <NUM> and the current collector <NUM> are on the opposite side of the separator <NUM>.

<FIG> depicts a line graph <NUM> illustrating a charge profile of the battery cell <NUM> consistent with implementations of the current subject matter. Referring to <FIG>, the line graph <NUM> illustrates the capacity of the battery cell <NUM> relative to the charge voltage voltage of the battery cell <NUM>, as measured at room temperature.

In some implementations of the current subject matter, the protective layer <NUM> is formed from polyamideimides, polyimides, polytetrafluoroethylene (PTFE), carboxymethyl cellulose (CMC), polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA), styrene butadiene rubber (SBR), and/or mixtures thereof. In some implementations of the current subject matter, the protective layer <NUM> is formed from a polyimide. In some implementations of the current subject matter, the protective layer <NUM> is formed from a carboxymethyl cellulose. In some implementations of the current subject matter, the protective layer <NUM> is formed from a crosslinkable polymer. Suitable crosslinkable polymers can include, for example, polybenzophenones, polyacrylates, polyvinyls, polystyrenes, polysulfones, <NUM>,<NUM>-dihydrofurancontaining polymers, carboxymethyl celluloses (CMC), polyamideimides, polyimides, styrene-containing copolymers, and mixtures thereof. In some implementations of the current subject matter, the crosslinkable polymer is a polyamideimide. In some implementations of the current subject matter, the crosslinkable polymer is a polyimide. In some implementations of the current subject matter, the crosslinkable polymer is a carboxymethyl cellulose.

In some implementations of the current subject matter, the protective layer <NUM> is formed from a crosslinked polymer. Suitable crosslinked polymers can include, for example, polybenzophenones, polyacrylates, polyvinyls, polystyrenes, polysulfones, <NUM>,<NUM>-dihydrofuran-containing polymers, carboxymethyl celluloses (CMC), polyamideimides, polyimides, styrene-containing copolymers, and/or mixtures thereof. In some implementations of the current subject matter, the crosslinked polymer is a polyamideimide. In some implementations of the current subject matter, the crosslinked polymer is a polyimide. In some implementations of the current subject matter, the crosslinked polymer is a carboxymethyl cellulose.

In some implementations of the current subject matter, the protective layer <NUM> is formed from a thermally crosslinkable polymer. Suitable thermally crosslinkable polymers can include, for example, polybenzophenones, polyacrylates, polyvinyls, polystyrenes, polysulfones, <NUM>,<NUM>-dihydrofuran-containing polymers, carboxymethyl celluloses (CMC), polyamideimides, polyimides, styrene-containing copolymers, and/or mixtures thereof. In some implementations of the current subject matter, the thermally crosslinkable polymer is a polyamideimide. In some implementations of the current subject matter, the thermally crosslinkable polymer is a polyimide. In some implementations of the current subject matter, the thermally crosslinkable polymer is a carboxymethyl cellulose.

In some implementations of the current subject matter, the protective layer <NUM> is formed from a photo crosslinkable polymer. Suitable photo crosslinkable polymers can include, for example, polybenzophenones, polyacrylates, polyvinyls, polystyrenes, polysulfones, <NUM>,<NUM>-dihydrofurancontaining polymers, styrene-containing copolymers, and/or mixtures thereof.

In some implementations of the current subject matter, the protective layer <NUM> is formed from its precursors via polymerization on the surface of the core of the coated electroactive particle (e.g., the dual function current collector <NUM>) provided herein. In some implementations of the current subject matter, the precursors of a polymer is monomers of the polymer. In some implementations of the current subject matter, the precursors of a polymer is crosslinkable polymers. In some implementations of the current subject matter, the polyamideimide forming the protective layer <NUM> is formed from a polyamideimide via crosslinking on the surface of the core of the coated electroactive particle (e.g., the dual function current collector <NUM>) provided herein. In some implementations of the current subject matter, the polyimide forming the protective layer <NUM> is formed from a polyimide via crosslinking on the surface of the core of the coated electroactive particle provided herein (e.g., the dual function current collector <NUM>).

In some implementations of the current subject matter, the protective layer <NUM> is formed from a polyamideimide, polyimide, and/or a mixture thereof. In some implementations of the current subject matter, the polyamideimide is aromatic, aliphatic, cycloaliphatic, and/or a mixture thereof. In some implementations of the current subject matter, the polyamideimide is an aromatic polyamideimide. In some implementations of the current subject matter, the polyamideimide is an aliphatic polyamideimide. In some implementations of the current subject matter, the polyamideimide is a cycloaliphatic polyamideimide. In some implementations of the current subject matter, the polyimide is aromatic, aliphatic, cycloaliphatic, and/or a mixture thereof. In some implementations of the current subject matter, the polyimide is an aromatic polyimide. In some implementations of the current subject matter, the polyimide is an aliphatic polyimide. In some implementations of the current subject matter, the polyimide is a cycloaliphatic polyimide.

In some implementations of the current subject matter, the protective layer <NUM> is formed from TORLON® AI-<NUM>, TORLON® AI-<NUM>, TORLON® <NUM>, or TORLON® <NUM> (e.g., manufactured by Solvay Advanced Polymers, L. of Augusta, GA). Alternately and/or additionally, the protective layer <NUM> is formed from U-VARNISH® (e.g., manufactured by UBE American Inc. of New York, NY). In some implementations of the current subject matter, the protective layer <NUM> is formed from TORLON® AI-<NUM>. In some implementations of the current subject matter, the protective layer <NUM> is formed from TORLON® AI-<NUM>. In some implementations of the current subject matter, the protective layer <NUM> is formed from TORLON® <NUM>. In some implementations of the current subject matter, the protective layer <NUM> is formed from TORLON® <NUM>. In some implementations of the current subject matter, the protective layer <NUM> is formed from U-VARNISH®. It should be appreciated that other suitable polyamideimide and polyimides can include those described in <NPL>; <NPL>; <NPL>; <NPL>; <NPL>; <NPL>; <NPL>; and <NPL>.

In some implementations of the current subject matter, the protective layer <NUM> is formed from a polyamideimide and a polyamine via polymerization on the surface of the core of the coated electroactive particle provided herein (e.g., the dual function current collector <NUM>).

In some implementations of the current subject matter, the protective layer <NUM> is formed from an aromatic, aliphatic, and/or cycloaliphatic polyimide via a condensation reaction of an aromatic, aliphatic, or cycloaliphatic polyanhydride. For instance, a dianhydride is combined with an aromatic, aliphatic, and/or cycloaliphatic polyamine to form a polyamic acid. Alternately, the dianhydride is combined with a diamine and/or a triamine to form the polyamic acid. The polyamic acid can subsequently be subject to chemical and/or thermal cyclization to form the polyimide. In some implementations of the current subject matter, the protective layer <NUM> is formed from a polyanhydride and a polyamine via polymerization on the surface of the core of the coated electroactive particle provided herein (e.g., the dual function current collector <NUM>).

In some implementations of the current subject matter, suitable polyanhydrides, polyamines, polyamideimide, and/or polyimides can include, for example, those described in Eur. <CIT> and <CIT>; <CIT>; and <CIT>and <CIT>.

In some implementations of the current subject matter, suitable polyanhydrides can include, for example, butanetetracarboxylic dianhydride, meso-<NUM>,<NUM>,<NUM>,<NUM>-butanetetracarboxylic dianhydride, dl-<NUM>,<NUM>,<NUM>,<NUM>-butanetetracarboxylic dianhydride, cyclobutane tetracarboxylic dianhydride, <NUM>,<NUM>,<NUM>,<NUM>-cyclopentane tetracarboxylic dianhydride, cyclohexane tetracarboxylic dianhydride, <NUM>,<NUM>,<NUM>,<NUM>-cyclohexanetetracarboxylic dianhydride, cis-<NUM>,<NUM>,<NUM>,<NUM>-cyclohexanetetracarboxylic dianhydride, trans-<NUM>,<NUM>,<NUM>,<NUM>-cyclohexanetetracarboxylic dianhydride, bicyclo[<NUM>. <NUM>]octane-<NUM>,<NUM>,<NUM>,<NUM>-tetracarboxylic <NUM>,<NUM>:<NUM>,<NUM>-dianhydride, bicyclo[<NUM>. <NUM>]oct-<NUM>-ene-<NUM>,<NUM>,<NUM>,<NUM>-tetracarboxylic dianhydride, bicyclo[<NUM>. <NUM>]-heptane-<NUM>,<NUM>,<NUM>,<NUM>-tetracarboxylic <NUM>,<NUM>:<NUM>,<NUM>-dianhydride, (4arH, 8acH)-decahydro-<NUM>,t,4t:5c,<NUM>-cyclohexene-<NUM>,<NUM>,<NUM>,<NUM>-tetracarboxylic <NUM>,<NUM>:<NUM>,<NUM>-dianhydride, bicyclo[<NUM>. <NUM>]heptane-<NUM>-exo-<NUM>-exo-<NUM>-exo-tricarboxyl-<NUM>-endo-acetic dianhydride, bicyclo[<NUM>. <NUM>]oxetane-<NUM>,<NUM>,<NUM>,<NUM>-tetracarboxylic acid intramolecular dianhydride, <NUM>,<NUM>',<NUM>,<NUM>'-diphenylsulfonetetracarboxylic dianhydride, <NUM>,<NUM>'-hexafluoropropylidene bisphthalic dianhydride, <NUM>,<NUM>-bis(<NUM>,<NUM>-dicarboxyphenyl)-<NUM>,<NUM>,<NUM>,<NUM>-tetramethyldisiloxane, and/or combinations thereof.

In some implementations of the current subject matter, suitable polyamines can include, for example, <NUM>,<NUM>'-methylenebis(<NUM>,<NUM>-dimethylaniline), <NUM>,<NUM>'-oxydianiline, m-phenylenediamine, p-phenylenediamine, benzidene, <NUM>,<NUM>-diaminobenzoic acid, o-dianisidine, <NUM>,<NUM>'-diaminodiphenyl methane, <NUM>,<NUM>'-methylenebis(<NUM>,<NUM>-dimethylaniline), <NUM>,<NUM>-diaminobutane, <NUM>,<NUM>-diaminohexane, <NUM>,<NUM>-diaminoheptane, <NUM>,<NUM>-diaminononane, <NUM>,<NUM>-diaminodecane, <NUM>,<NUM>-diaminododecane, <NUM>-amino-<NUM>,<NUM>,<NUM>-trimethylcyclohexanemethylamine, <NUM>,<NUM>-bis(aminomethyl)bicyclo[<NUM>. <NUM>]heptane, <NUM>,<NUM>-bis(aminomethyl)bicyclo[<NUM>. <NUM>]heptane, <NUM>,<NUM>-diaminotoluene, <NUM>,<NUM>-diamino-<NUM>-methoxybenzene, <NUM>,<NUM>-diamino-<NUM>-phenylbenzene and <NUM>,<NUM>-diamino-<NUM>-chlorobenzene, <NUM>,<NUM>'-diaminobiphenyl, <NUM>,<NUM>-bis(<NUM>-aminophenyl)propane, <NUM>,<NUM>-bis[<NUM>-(<NUM>-aminophenoxy)phenyl]propane, <NUM>,<NUM>-bis(<NUM>-aminophenyl)-<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>-hexafluoropropane, <NUM>,<NUM>-bis(<NUM>-aminophenoxyphenyl)hexafluoropropane, <NUM>,<NUM>'-diaminodiphenyl ether, <NUM>,<NUM>-diaminodiphenyl ether, <NUM>,<NUM>-bis(<NUM>-aminophenoxy)benzene, <NUM>,<NUM>-bis(<NUM>-aminophenoxy)benzene, <NUM>,<NUM>-bis(<NUM>-aminophenoxy)benzene, <NUM>,<NUM>'-bis(<NUM>-aminophenoxy)biphenyl, <NUM>,<NUM>'-bis(<NUM>-aminophenoxy)biphenyl, <NUM>,<NUM>-bis[<NUM>-(<NUM>-aminophenoxy)phenyl]propane, <NUM>,<NUM>-bis[<NUM>-(<NUM>-aminophenoxy)phenyl]propane, <NUM>,<NUM>-bis[<NUM>-(<NUM>-aminophenoxy)phenyl]-<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>-hexafluoropropane, <NUM>,<NUM>'-diaminodiphenyl thioether, <NUM>,<NUM>'-diaminodiphenyl sulfone, <NUM>,<NUM>'-diaminobenzophenone, <NUM>,<NUM>'-diaminobenzophenone, naphthalene diamines (including <NUM>,<NUM>-diaminonaphthalene and <NUM>,<NUM>-diaminonaphthalene), <NUM>,<NUM>-diaminopyridine, <NUM>,<NUM>-diaminopyrimidine, <NUM>,<NUM>-diamino-s-triazine, <NUM>,<NUM>-diamino-<NUM>-(aminomethyl)octane, bis[<NUM>-(<NUM>-aminophenoxy)-phenyl]sulfone, <NUM>,<NUM>'-dihydroxy-<NUM>,<NUM>'-diaminobiphenyl, <NUM>,<NUM>-bis(<NUM>-amino-<NUM>-hydroxyphenyl)hexafluoropropane, <NUM>,<NUM>-bis(<NUM>-hydroxy-<NUM>-aminophenyl)propane, and/or combinations thereof.

In some implementations of the current subject matter, the polyimide is poly(<NUM>,<NUM>'-phenyleneoxyphenylene pyromellitic imide) and/or poly(<NUM>,<NUM>'-phenyleneoxyphenylene-co-<NUM>,<NUM>-phenylenebenzophenonetetracarboxylic diimide).

Claim 1:
A method of manufacturing a battery cell (<NUM>), comprising the steps of:
forming a battery cell (<NUM>) by
providing a separator (<NUM>);
providing a first current collector (<NUM>);
applying a protective layer (<NUM>) directly to the surface of the first current collector (<NUM>), the first current collector (<NUM>) and the protective layer (<NUM>) being disposed on one side of the separator (<NUM>); wherein the protective layer (<NUM>) is disposed between the first current collector (<NUM>) and the separator (<NUM>), and wherein the protective layer (<NUM>) is formed from a polymer and/or a polymer composite that includes a plurality of different polymers;
disposing a first electrode (<NUM>) on an opposite side of the separator (<NUM>) as the first current collector (<NUM>) and the protective layer (<NUM>); wherein the first electrode is formed from a lithium cobalt oxide (LiCoO<NUM>), lithium nickel cobalt oxide (LiNiCoO<NUM>), lithium manganese nickel cobalt oxide (LiNiMnCoO<NUM>), lithium manganese silicon oxide (Li<NUM>MnSiO<NUM>), lithium iron phosphate (LiFePO<NUM>), lithium fluoride (LiF), and/or lithium sulfide (Li<NUM>S);
filling the battery cell casing with a liquid electrolyte (<NUM>, <NUM>) to render the protective layer (<NUM>) ionically conductive; and
subjecting the battery cell to charging, thereby causing lithium metal to be extracted from the first electrode (<NUM>) and deposited between the first current collector (<NUM>) and the protective layer (<NUM>), wherein the deposit of the metal forms a lithium metal electrode as a second electrode (<NUM>) in situ between the first current collector (<NUM>) and the protective layer (<NUM>), wherein the lithium metal extracted from the first electrode (<NUM>) and deposited between the first current collector (<NUM>) and the protective layer (<NUM>) comprises dendrites, and wherein the protective layer (<NUM>) prevents the dendrites forming the second electrode (<NUM>) from penetrating the separator (<NUM>) and causing an internal short within the battery (<NUM>).