POLYMERIC GEL ELECTROLYTE SYSTEMS FOR HIGH-POWER SOLID-STATE BATTERY

The present disclosure provides a polymeric gel electrolyte for an electrochemical cell that cycles lithium ions. The polymeric gel electrolyte includes greater than or equal to about 0.1 wt. % to less than or equal to about 10 wt. % of a non-lithium salt. The non-lithium salt includes a non-lithium cation having an ion radius that is greater than or equal to about 80% to less than or equal to about 250% of an ion radius of a lithium ion. The polymeric gel electrolyte further includes greater than or equal to about 50 wt. % to less than or equal to about 99.9 wt. % of a non-volatile gel. The non-volatile gel includes greater than or equal to 0 wt. % to less than or equal to about 50 wt. % of a polymeric host and greater than or equal to about 5 wt. % to less than or equal to about 100 wt. % of a liquid electrolyte.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit and priority of Chinese Patent Application No. 202111049241.1 filed Sep. 8, 2021. The entire disclosure of the above application is incorporated herein by reference.

INTRODUCTION

Electrochemical energy storage devices, such as lithium-ion batteries, can be used in a variety of products, including automotive products such as start-stop systems (e.g., 12V start-stop systems), battery-assisted systems (“μBAS”), Hybrid Electric Vehicles (“HEVs”), and Electric Vehicles (“EVs”). Typical lithium-ion batteries include two electrodes and an electrolyte component and/or separator. One of the two electrodes can serve as a positive electrode or cathode, and the other electrode can serve as a negative electrode or anode. Lithium-ion batteries may also include various terminal and packaging materials. Rechargeable lithium-ion batteries operate by reversibly passing lithium ions back and forth between the negative electrode and the positive electrode. For example, lithium ions may move from the positive electrode to the negative electrode during charging of the battery and in the opposite direction when discharging the battery. A separator and/or electrolyte may be disposed between the negative and positive electrodes. The electrolyte is suitable for conducting lithium ions between the electrodes and, like the two electrodes, may be in a solid form, a liquid form, or a solid-liquid hybrid form. In instances of solid-state batteries, which include a solid-state electrolyte layer disposed between the solid-state electrodes, the solid-state electrolyte physically separates the solid-state electrodes so that a distinct separator is not required.

Semi-solid and solid-state batteries have advantages over batteries that include a separator and a liquid electrolyte. These advantages can include a longer shelf life with lower self-discharge, simpler thermal management, a reduced need for packaging, and the ability to operate within a wider temperature window. For example, semi-solid electrolytes and/or solid-state electrolytes are generally non-volatile and non-flammable, so as to allow cells to be cycled under harsher conditions without experiencing diminished potential or thermal runaway, which can potentially occur with the use of liquid electrolytes. However, solid-state batteries often experience comparatively low power capabilities. Low power capabilities may be a result of interfacial resistance within the solid-state electrodes and/or at the electrode, and a solid-state electrolyte layer interfacial resistance caused by limited contact, or void spaces, between the solid-state active particles and/or the solid-state electrolyte particles. Accordingly, it would be desirable to develop high-performance solid-state and/or semi-solid battery designs, materials, and methods that improve power capabilities, as well as energy density.

SUMMARY

The present disclosure relates to solid-state batteries, for example to bipolar solid-state batteries, including a polymeric gel electrolyte system and exhibiting enhanced interfacial contact (both micro and macro), and to methods for forming the same.

In various aspects, the present disclosure provides a polymeric gel electrolyte for an electrochemical cell that cycles lithium ions. The polymeric gel electrolyte may include greater than or equal to about 0.1 wt. % to less than or equal to about 10 wt. % of a non-lithium salt.

In one aspect, the non-lithium salt may include a non-lithium cation having an ion radius that is greater than or equal to about 80% to less than or equal to about 250% of an ion radius of a lithium ion.

In one aspect, the non-lithium cation may be selected from the group consisting of: sodium (Na+), calcium (Ca2+), magnesium (Mg2+), potassium (K+), aluminum (Al3+), iron (Fe2+), manganese (Mn2+), strontium (Sr2+), zinc (Zn2+), and combinations thereof.

In one aspect, the non-lithium salt may be selected from the group consisting of: magnesium bis(trifluoromethanesulfonyl)imide (Mg(TFSI)2), calcium bis(trifluoromethanesulfonyl)imide (Ca(TFSI)2), potassium bis(trifluoromethanesulfonyl)imide (KTFSI), sodium nitrate (NaNO3), sodium hexafluorophosphate(NaPF6), and combinations thereof.

In one aspect, the polymeric gel electrolyte system may further include greater than or equal to about 50 wt. % to less than or equal to about 99.9 wt. % of a non-volatile gel. The non-volatile gel may include a liquid electrolyte.

In one aspect, the non-volatile gel may further include a polymeric host. For example, the non-volatile gel may include greater than 0 wt. % to less than or equal to about 50 wt. % of the polymeric host, and greater than or equal to about 5 wt. % to less than or equal to about 99.9 wt. % of the liquid electrolyte.

In one aspect, the liquid electrolyte may include a lithium salt and a solvent. The lithium salt may be selected from the group consisting of: lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(pentafluoroethanesulfonyl)imide (LiBETI), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium trifluoromethyl sulfonate (LiTFO), lithium difluoro(oxalato)borate (LiDFOB), and combinations thereof. The solvent may be selected from the group consisting of: ethylene carbonate (EC), propylene carbonate (PC), gamma-butyrolactone (GBL), tetraethyl phosphate (TEP), fluoroethylene carbonate (FEC), and combinations thereof.

In one aspect, the non-volatile gel may further include greater than 0 wt. % to less than or equal to about 10 wt. % of an additive. The additive may be selected from the group consisting of: vinylene carbonate (VC), fluoroethylene carbonate (FEC), vinylethylene carbonate (VEC), butylene carbonate (BC), ethylene sulfite (ES), propylene sulfite (PS), and combinations thereof.

In various aspects, the present disclosure provides an electrochemical cell that cycles lithium ions. The electrochemical cell may include a first electrode, a second electrode, and an electrolyte layer disposed between the first electrode and the second electrode. The first electrode may include a first solid-state electroactive material. The second electrode may include a second solid-state electroactive material. At least one of the first electrode, the second electrode, and the electrolyte layer may include a polymeric gel electrolyte. The polymeric gel electrolyte may include greater than or equal to about 0.1 wt. % to less than or equal to about 10 wt. % of a non-lithium salt.

In one aspect, the electrolyte layer may include a plurality of solid-state electrolyte particles and the polymeric gel electrolyte system may at least partially fill void spaces between the solid-state electrolyte particles.

In one aspect, the electrolyte layer may include a free-standing membrane defined by the polymeric gel electrolyte system. The free-standing membrane may have a thickness greater than or equal to about 5 μm to less than or equal to about 1,000 μm.

In one aspect, the second solid-state electroactive material may be a two-dimensional electroactive material.

In one aspect, the polymeric gel electrolyte system may include a first polymeric gel electrolyte that at least partially fills void spaces in the first solid-state electroactive material, and a second polymeric gel electrolyte that at least partially fills void spaces in the second solid-state electroactive material.

In one aspect, the non-lithium salt may include a non-lithium cation having an ion radius that is greater than or equal to about 80% to less than or equal to about 250% of an ion radius of a lithium ion.

In one aspect, the non-lithium cation may be selected from the group consisting of: sodium (Na+), calcium (Ca2+), magnesium (Mg2+), potassium (K+), aluminum (Al3+), iron (Fe2+), manganese (Mn2+), strontium (S2+), zinc (Zn2+), and combinations thereof.

In one aspect, the polymeric gel electrolyte system may further include greater than or equal to about 50 wt. % to less than or equal to about 99.9 wt. % of a non-volatile gel. The non-volatile gel may include greater than or equal to 0 wt. % to less than or equal to about 50 wt. % of a polymeric host, and greater than or equal to about 5 wt. % to less than or equal to about 100 wt. % of a liquid electrolyte.

In one aspect, the non-volatile gel may further include greater than 0 wt. % to less than or equal to about 10 wt. % of an additive. The additive may be selected from the group consisting of: vinylene carbonate (VC), fluoroethylene carbonate (FEC), vinylethylene carbonate (VEC), butylene carbonate (BC), ethylene sulfite (ES), propylene sulfite (PS), and combinations thereof.

In various aspects, the present disclosure provides an electrochemical cell that cycles lithium ions. The electrochemical cell may include a first electrode, a second electrode, and an electrolyte layer disposed between the first electrode and the second electrode. The first electrode may include a first solid-state electroactive material. The second electrode may include a second solid-state electroactive material. At least one of the first electrode, the second electrode, and the electrolyte layer may include a polymeric gel electrolyte system. The polymeric gel electrolyte system may include greater than or equal to about 0.1 wt. % to less than or equal to about 10 wt. % of a non-lithium salt and greater than or equal to about 50 wt. % to less than or equal to about 99.9 wt. % of a non-volatile gel. The non-lithium salt may include a non-lithium cation selected from the group consisting of: sodium (Na+), calcium (Ca2+), magnesium (Mg2+), potassium (K+), aluminum (Al3+), iron (Fe2+), manganese (Mn2+), strontium (Sr2+), zinc (Zn2+), and combinations thereof. The non-volatile gel may include greater than or equal to 0 wt. % to less than or equal to about 50 wt. % of a polymeric host, and greater than or equal to about 5 wt. % to less than or equal to about 100 wt. % of a liquid electrolyte.

DETAILED DESCRIPTION

The current technology pertains to solid-state batteries (SSBs), for example only, bipolar solid-state batteries, and methods of forming and using the same. Solid-state batteries may include at least one solid component, for example, at least one solid electrode, but may also include semi-solid or gel, liquid, or gas components, in certain variations. Solid-state batteries may have a bipolar stack design comprising a plurality of bipolar electrodes where a first mixture of solid-state electroactive material particles (and optional solid-state electrolyte particles) is disposed on a first side of a current collector, and a second mixture of solid-state electroactive material particles (and optional solid-state electrolyte particles) is disposed on a second side of the current collector that is substantially parallel with the first side. The first mixture may include, as the solid-state electroactive material particles, positive electrode or cathode material particles. The second mixture may include, as solid-state electroactive material particles, negative electrode or anode material particles. A series or stack of the bipolar electrodes forming the exemplary solid-state batteries may be physically separated by a separator and/or a solid-state electrolyte comprising solid-state electrolyte particles. The solid-state electrolyte particles in each instance may be the same or different.

Such solid-state batteries may be incorporated into energy storage devices, like rechargeable lithium-ion batteries, which may be used in automotive transportation applications (e.g., motorcycles, boats, tractors, buses, mobile homes, campers, and tanks). The present technology, however, may also be used in other electrochemical devices, including aerospace components, consumer goods, devices, buildings (e.g., houses, offices, sheds, and warehouses), office equipment and furniture, and industrial equipment machinery, agricultural or farm equipment, or heavy machinery, by way of non-limiting example. In various aspects, the present disclosure provides a rechargeable lithium-ion battery that exhibits high temperature tolerance, as well as improved safety and superior power capability and life performance.

An exemplary and schematic illustration of a solid-state electrochemical cell unit (also referred to as a “solid-state battery” and/or “battery”)20that cycles lithium ions is shown inFIGS.1A and1B. The battery20includes a negative electrode (i.e., anode)22, a positive electrode (i.e., cathode)24, and an electrolyte layer26that occupies a space between the two or more electrodes. The electrolyte layer26may be a solid-state or semi-solid state separating layer that physically separates the negative electrode22from the positive electrode24. The electrolyte layer26may include a first plurality of solid-state electrolyte particles30. A second plurality of solid-state electrolyte particles90may be mixed with negative solid-state electroactive particles50in the negative electrode22, and a third plurality of solid-state electrolyte particles92may be mixed with positive solid-state electroactive particles60in the positive electrode24, so as to form a continuous electrolyte network, which may be a continuous lithium-ion conduction network.

A first bipolar current collector32may be positioned at or near the negative electrode22. A second bipolar current collector34may be positioned at or near the positive electrode24. The first and second bipolar current collectors32,34may be the same or different. For example, the first and second bipolar current collectors32,34may each have a thickness greater than or equal to about 2 μm to less than or equal to about 30 μm. The first and second bipolar current collectors32,34may each have a thickness greater than or equal to 2 μm to less than or equal to 30 μm. The first and second bipolar current collectors32,34may each be metal foils including at least one of stainless steel, aluminum, nickel, iron, titanium, copper, tin, alloys thereof, or any other electrically conductive material known to those of skill in the art.

In certain variations, the first bipolar current collector34and/or the second bipolar current collector34may be a cladded foil, for example, where one side (e.g., the first side or the second side) of the current collector32,34includes one metal (e.g., first metal) and another side (e.g., the other side of the first side or the second side) of the current collector232includes another metal (e.g., second metal). The cladded foil may include, for example only, aluminum-copper (Al—Cu), nickel-copper (Ni—Cu), stainless steel-copper (SS-Cu), aluminum-nickel (Al—Ni), aluminum-stainless steel (Al-SS), and nickel-stainless steel (Ni-SS). In certain variations, the first bipolar current collector232A and/or second bipolar current collectors232B may be pre-coated, such as graphene or carbon-coated aluminum current collectors.

In each instance, the first bipolar current collector32and the second bipolar current collector34respectively collect and move free electrons to and from an external circuit40(as shown by the block arrows). For example, an interruptible external circuit40and a load device42may connect the negative electrode22(through the first bipolar current collector32) and the positive electrode24(through the second bipolar current collector34).

The battery20can generate an electric current (indicated by arrows inFIGS.1A and1B) during discharge by way of reversible electrochemical reactions that occur when the external circuit40is closed (to connect the negative electrode22and the positive electrode24) and when the negative electrode22has a lower potential than the positive electrode24. The chemical potential difference between the negative electrode22and the positive electrode24drives electrons produced by a reaction, for example, the oxidation of intercalated lithium, at the negative electrode22, through the external circuit40toward the positive electrode24. Lithium ions, which are also produced at the negative electrode22, are concurrently transferred through the electrolyte layer26toward the positive electrode24. The electrons flow through the external circuit40and the lithium ions migrate across the electrolyte layer26to the positive electrode24, where they may be plated, reacted, or intercalated. The electric current passing through the external circuit40can be harnessed and directed through the load device42(in the direction of the arrows) until the lithium in the negative electrode22is depleted and the capacity of the battery20is diminished.

The battery20can be charged or reenergized at any time by connecting an external power source (e.g., charging device) to the battery20to reverse the electrochemical reactions that occur during battery discharge. The external power source that may be used to charge the battery20may vary depending on the size, construction, and particular end-use of the battery20. Some notable and exemplary external power sources include, but are not limited to, an AC-DC converter connected to an AC electrical power grid though a wall outlet and a motor vehicle alternator. The connection of the external power source to the battery20promotes a reaction, for example, non-spontaneous oxidation of intercalated lithium, at the positive electrode24so that electrons and lithium ions are produced. The electrons, which flow back toward the negative electrode22through the external circuit40, and the lithium ions, which move across the electrolyte layer26back toward the negative electrode22, reunite at the negative electrode22and replenish it with lithium for consumption during the next battery discharge cycle. As such, a complete discharging event followed by a complete charging event is considered to be a cycle, where lithium ions are cycled between the positive electrode24and the negative electrode22.

Although the illustrated example includes a single positive electrode24and a single negative electrode22, the skilled artisan will recognize that the current teachings apply to various other configurations, including those having one or more cathodes and one or more anodes, as well as various current collectors and current collector films with electroactive particle layers disposed on or adjacent to or embedded within one or more surfaces thereof. Likewise, it should be recognized that the battery20may include a variety of other components that, while not depicted here, are nonetheless known to those of skill in the art. For example, the battery20may include a casing, a gasket, terminal caps, and any other conventional components or materials that may be situated within the battery20, including between or around the negative electrode22, the positive electrode24, and/or the electrolyte layer26.

In many configurations, each of the negative electrode current collector32, the negative electrode22, the electrolyte layer26, the positive electrode24, and the positive electrode current collector34are prepared as relatively thin layers (for example, from several microns to a millimeter or less in thickness) and assembled in layers connected in series arrangement to provide a suitable electrical energy, battery voltage and power package, for example, to yield a Series-Connected Elementary Cell Core (“SECC”). In various other instances, the battery20may further include electrodes22,24connected in parallel to provide suitable electrical energy, battery voltage, and power for example, to yield a Parallel-Connected Elementary Cell Core (“PECC”).

The size and shape of the battery20may vary depending on the particular applications for which it is designed. Battery-powered vehicles and hand-held consumer electronic devices are two examples where the battery20would most likely be designed to different size, capacity, voltage, energy, and power-output specifications. The battery20may also be connected in series or parallel with other similar lithium-ion cells or batteries to produce a greater voltage output, energy, and power if it is required by the load device42. The battery20can generate an electric current to the load device42that can be operatively connected to the external circuit40. The load device42may be fully or partially powered by the electric current passing through the external circuit40when the battery20is discharging. While the load device42may be any number of known electrically-powered devices, a few specific examples of power-consuming load devices include an electric motor for a hybrid vehicle or an all-electric vehicle, a laptop computer, a tablet computer, a cellular phone, and cordless power tools or appliances, by way of non-limiting example. The load device42may also be an electricity-generating apparatus that charges the battery20for purposes of storing electrical energy.

With renewed reference toFIGS.1A and1B, the electrolyte layer26, which may be a semi-solid, provides electrical separation—preventing physical contact—between the negative electrode22and the positive electrode24. The electrolyte layer26also provides a minimal resistance path for internal passage of ions. In various aspects, the electrolyte layer26may be defined by a first plurality of solid-state electrolyte particles30. For example, the electrolyte layer26may be in the form of a layer or a composite that comprises the first plurality of solid-state electrolyte particles30.

The solid-state electrolyte particles30may have an average particle diameter greater than or equal to about 0.02 μm to less than or equal to about 20 urn, optionally greater than or equal to about 0.1 μm to less than or equal to about 10 urn, and in certain aspects, optionally greater than or equal to about 0.1 μm to less than or equal to about 1 μm. The electrolyte layer26may be in the form of a layer having a thickness greater than or equal to about 1 μm to less than or equal to about 1,000 μm, optionally greater than or equal to about 5 μm to less than or equal to about 200 μm, optionally greater than or equal to about 10 μm to less than or equal to about 100 μm, optionally about 40 μm, and in certain aspects, optionally about 30 μm. The electrolyte layer26may have an interparticle porosity80between the solid-state electrolyte particles30that is greater than 0 vol. % to less than or equal to about 50 vol. %, optionally greater than or equal to about 1 vol. % to less than or equal to about 40 vol. %, and in certain aspects, optionally greater than or equal to about 2 vol. % to less than or equal to about 20 vol. %.

The solid-state electrolyte particles30may have an average particle diameter greater than or equal to 0.02 μm to less than or equal to 20 μm, optionally greater than or equal to 0.1 μm to less than or equal to 10 μm, and in certain aspects, optionally greater than or equal to 0.1 μm to less than or equal to 1 μm. The electrolyte layer26may be in the form of a layer having a thickness greater than or equal to 1 μm to less than or equal to 1,000 μm, optionally greater than or equal to 5 μm to less than or equal to 200 μm, optionally greater than or equal to 10 μm to less than or equal to 100 μm, optionally 40 μm, and in certain aspects, optionally 30 μm. The electrolyte layer26may have an interparticle porosity80between the solid-state electrolyte particles30that is greater than 0 vol. % to less than or equal to 50 vol. %, optionally greater than or equal to 1 vol. % to less than or equal to 40 vol. %, and in certain aspects, optionally greater than or equal to 2 vol. % to less than or equal to 20 vol. %.

In certain variations, the oxide-based particles may comprise one or more garnet ceramics, LISICON-type oxides, NASICON-type oxides, and Perovskite type ceramics. For example, the garnet ceramics may be selected from the group consisting of: Li7La3Zr2O12, Li6.2Ga0.3La2.95Rb0.05Zr2O12, Li6.85La2.9Ca0.1Zr1.75Nb0.25O12, Li6.25Al0.25La3Zr2O12, Li6.75La3Zr1.75Nb0.25O12, and combinations thereof. The LISICON-type oxides may be selected from the group consisting of: Li2+2xZn1−xGeO4(where 0<x<1), Li14Zn(GeO4)4, Li3+x(P1−xSix)O4(where 0<x<1), Li3+xGexV1−xO4(where 0<x<1), and combinations thereof. The NASICON-type oxides may be defined by LiMM′(PO4)3, where M and M′ are independently selected from Al, Ge, Ti, Sn, Hf, Zr, and La. For example, in certain variations, the NASICON-type oxides may be selected from the group consisting of: Li1+xAlxGe2−x(PO4)3(LAGP) (where 0≤x≤2), Li1.4Al0.4Ti1.6(PO4)3, Li1.3Al0.3Ti1.7(PO4)3, LiTi2(PO4)3, LiGeTi(PO4)3, LiGe2(PO4)3, LiHf2(PO4)3, and combinations thereof. The Perovskite-type ceramics may be selected from the group consisting of: Li3.3La0.53TiO3, LiSr1.65Zr1.3Ta1.709, Li2x-ySr1−xTayZr1−yO3(where x=0.75y and 0.60<y<0.75), Li3/8Sr7/16Nb3/4Zr1/4O3, Li3xLa(2/3−x)TiO3(where 0<x<0.25), and combinations thereof.

Although not illustrated, the skilled artisan will recognize that in certain instances, one or more binder particles may be mixed with the solid-state electrolyte particles30. For example, in certain aspects, the electrolyte layer26may include greater than or equal to 0 wt. % to less than or equal to about 10 wt. %, and in certain aspects, optionally greater than or equal to about 0.5 wt. % to less than or equal to about 10 wt. %, of the one or more binders. The electrolyte layer26may include greater than or equal to 0 wt. % to less than or equal to 10 wt. %, and in certain aspects, optionally greater than or equal to 0.5 wt. % to less than or equal to 10 wt. %, of the one or more binders. The one or more polymeric binders may include, for example only, polyvinylidene difluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene propylene diene monomer (EPDM) rubber, nitrile butadiene rubber (NBR), styrene-butadiene rubber (SBR), and lithium polyacrylate (LiPAA).

The negative electrode22may be formed from a lithium host material that is capable of functioning as a negative terminal of a lithium-ion battery. The negative electrode22may be in the form of a layer having a thickness greater than or equal to about 1 μm to less than or equal to about 1000 μm, optionally greater than or equal to about 5 μm to less than or equal to about 400 μm, and in certain aspects, optionally greater than or equal to about 10 μm to less than or equal to about 300 μm. The negative electrode22may be in the form of a layer having a thickness greater than or equal to 1 μm to less than or equal to 1000 μm, optionally greater than or equal to 5 μm to less than or equal to 400 μm, and in certain aspects, optionally greater than or equal to 10 μm to less than or equal to 300 μm. In certain variations, the negative electrode22may be defined by a plurality of the negative solid-state electroactive particles50. The negative solid-state electroactive particles50may have an average particle diameter greater than or equal to about 0.01 μm to less than or equal to about 50 μm, and in certain aspects, optionally greater than or equal to about 1 μm to less than or equal to about 20 μm. The negative solid-state electroactive particles50may have an average particle diameter greater than or equal to 0.01 μm to less than or equal to 50 μm, and in certain aspects, optionally greater than or equal to 1 μm to less than or equal to 20 μm.

The second plurality of solid-state electrolyte particles90may be the same as or different from the first plurality of solid-state electrolyte particles30. In certain variations, the negative solid-state electroactive particles50may comprise one or more carbonaceous negative electroactive materials, such as graphite, mesocarbon microbeads (MCMB), graphite carbon fiber, expanded graphite, soft carbon, hard carbon, nature graphite, graphene, carbon nanotubes (CNTs). In other variations, the negative solid-state electroactive particles50may be silicon-based comprising, for example, a silicon alloy and/or silicon-graphite mixture. The negative solid-state electroactive particles50may include a two-dimensional material, such as two-dimensional transition metal dichalcogenides (e.g., a layered MoS2, which may have an interlayer thickness of about 0.62 nm) and/or a two-dimensional silicon.

In certain instances, as illustrated, the negative electrode22may be a composite comprising a mixture of the negative solid-state electroactive particles50and the second plurality of solid-state electrolyte particles90. For example, the negative electrode22may include greater than or equal to about 30 wt. % to less than or equal to about 99.5 wt. %, and in certain aspects, optionally greater than or equal to about 50 wt. % to less than or equal to about 95 wt. %, of the negative solid-state electroactive particles50, and greater than or equal to 0 wt. % to less than or equal to about 70 wt. %, optionally greater than or equal to 0 wt. % to less than or equal to about 50 wt. %, and in certain aspects, optionally greater than or equal to about 5 wt. % to less than or equal to about 20 wt. %, of the second plurality of solid-state electrolyte particles90. The negative electrode22may include greater than or equal to 30 wt. % to less than or equal to 99.5 wt. %, and in certain aspects, optionally greater than or equal to 50 wt. % to less than or equal to 95 wt. %, of the negative solid-state electroactive particles50, and greater than or equal to 0 wt. % to less than or equal to 70 wt. %, optionally greater than or equal to 0 wt. % to less than or equal to 50 wt. %, and in certain aspects, optionally greater than or equal to 5 wt. % to less than or equal to 20 wt. %, of the second plurality of solid-state electrolyte particles90.

The second plurality of solid-state electrolyte particles90may be the same as or different from the first plurality of solid-state electrolyte particles30and/or the third plurality of solid-state electrolyte particles92. The negative electrodes22may have an interparticle porosity82between the negative solid-state electroactive particles50and/or the solid-state electrolyte particles90that is greater than or equal to 0 vol. % to less than or equal to about 50 vol. %, and in certain aspects, optionally greater than or equal to about 2 vol. % to less than or equal to about 20 vol. %. The negative electrodes22may have an interparticle porosity82between the negative solid-state electroactive particles50and/or the solid-state electrolyte particles90that is greater than or equal to 0 vol. % to less than or equal to 50 vol. %, and in certain aspects, optionally greater than or equal to 2 vol. % to less than or equal to 20 vol. %.

Although not illustrated, in certain variations, the negative electrode22may include one or more conductive additives and/or binder materials. For example, the negative solid-state electroactive particles50(and/or optional second plurality of solid-state electrolyte particles90) may be optionally intermingled with one or more electrically conductive materials (not shown) that provide an electron conduction path and/or at least one polymeric binder material (not shown) that improves the structural integrity of the negative electrode22.

The negative electrode22may include greater than or equal to 0 wt. % to less than or equal to about 30 wt. %, and in certain aspects, optionally greater than or equal to about 2 wt. % to less than or equal to about 10 wt. %, of the one or more electrically conductive additives; and greater than or equal to 0 wt. % to less than or equal to about 20 wt. %, and in certain aspects, optionally greater than or equal to about 1 wt. % to less than or equal to about 10 wt. %, of the one or more binders.

The negative electrode22may include greater than or equal to 0 wt. % to less than or equal to 30 wt. %, and in certain aspects, optionally greater than or equal to 2 wt. % to less than or equal to 10 wt. %, of the one or more electrically conductive additives; and greater than or equal to 0 wt. % to less than or equal to 20 wt. %, and in certain aspects, optionally greater than or equal to 1 wt. % to less than or equal to 10 wt. %, of the one or more binders.

The positive electrode24may be formed from a lithium-based or electroactive material that can undergo lithium intercalation and deintercalation while functioning as the positive terminal of the battery20. The positive electrode24may be in the form of a layer having a thickness greater than or equal to about 1 μm to less than or equal to about 1,000 μm, optionally greater than or equal to about 5 μm to less than or equal to about 400 μm, and in certain aspects, optionally greater than or equal to about 10 μm to less than or equal to about 300 μm. The positive electrode24may be in the form of a layer having a thickness greater than or equal to 1 μm to less than or equal to 1,000 μm, optionally greater than or equal to 5 μm to less than or equal to 400 μm, and in certain aspects, optionally greater than or equal to 10 μm to less than or equal to 300 μm

In certain variations, the positive electrode24may be defined by a plurality of the positive solid-state electroactive particles60. The positive solid-state electroactive particles60may have an average particle diameter greater than or equal to about 0.01 μm to less than or equal to about 50 μm, and in certain aspects, optionally greater than or equal to about 1 μm to less than or equal to about 20 μm. The positive solid-state electroactive particles60may have an average particle diameter greater than or equal to 0.01 μm to less than or equal to 50 μm, and in certain aspects, optionally greater than or equal to 1 μm to less than or equal to 20 μm.

In certain variations, the positive electrode24may be one of a layered-oxide cathode, a spinel cathode, and a polyanion cathode. For example, in the instances of a layered-oxide cathode (e.g., rock salt layered oxides), the positive solid-state electroactive particles60may comprise one or more positive electroactive materials selected from LiCoO2, LiNixMnyCo1−x−yO2(where 0≤x≤1 and 0≤y≤1), LiNixMnyAl1−x−yO2(where 0<x<1 and 0<y<1), LiNixMn1-xO2(where 0≤x≤1), and Li1+xMO2(where 0≤x≤1) for solid-state lithium-ion batteries. The spinel cathode may include one or more positive electroactive materials, such as LiMn2O4and LiNi0.5Mn1.5O4. The polyanion cation may include, for example, a phosphate, such as LiFePO4, LiVPO4, LiV2(PO4)3, Li2FePO4F, Li3Fe3(PO4)4, or Li3V2(PO4)F3for lithium-ion batteries, and/or a silicate, such as LiFeSiO4for lithium-ion batteries. In this fashion, in various aspects, the positive solid-state electroactive particles60may comprise one or more positive electroactive materials selected from the group consisting of LiCoO2, LiNixMnyCo1−x−yO2(where 0≤x≤1 and 0≤y≤1), LiNixMn1−xO2(where 0≤x≤1), Li1+xMO2(where 0≤x≤1), LiMn2O4, LiMxMn1.5O4, LiFePO4, LiVPO4, LiV2(PO4)3, Li2FePO4F, Li3Fe3(PO4)4, Li3V2(PO4)F3, LiFeSiO4, and combinations thereof. In certain aspects, the positive solid-state electroactive particles60may be coated (for example, by LiNbO3and/or Al2O3) and/or the positive electroactive material may be doped (for example, by aluminum and/or magnesium).

In certain variations, as illustrated, the positive electrode24is a composite comprising a mixture of the positive solid-state electroactive particles60and the third plurality of solid-state electrolyte particles92. For example, the positive electrode24may include greater than or equal to about 30 wt. % to less than or equal to about 98 wt. %, and in certain aspects, optionally greater than or equal to about 50 wt. % to less than or equal to about 95 wt. %, of the positive solid-state electroactive particles60, and greater than or equal to 0 wt. % to less than or equal to about 70 wt. %, optionally greater than or equal to 0 wt. % to less than or equal to about 50 wt. %, and in certain aspects, optionally greater than or equal to about 5 wt. % to less than or equal to about 20 wt. %, of the third plurality of solid-state electrolyte particles92.

The positive electrode24may include greater than or equal to 30 wt. % to less than or equal to 98 wt. %, and in certain aspects, optionally greater than or equal to 50 wt. % to less than or equal to 95 wt. %, of the positive solid-state electroactive particles60, and greater than or equal to 0 wt. % to less than or equal to 70 wt. %, optionally greater than or equal to 0 wt. % to less than or equal to 50 wt. %, and in certain aspects, optionally greater than or equal to 5 wt. % to less than or equal to 20 wt. %, of the third plurality of solid-state electrolyte particles92.

The third plurality of solid-state electrolyte particles92may be the same as or different from the first and/or second pluralities of solid-state electrolyte particles30,90. The positive electrodes24may have an interparticle porosity84between the positive solid-state electroactive particles60and/or the solid-state electrolyte particles92that is greater than or equal to 0 vol. % to less than or equal to about 50 vol. %, and in certain aspects, optionally greater than or equal to about 2 vol. % to less than or equal to about 20 vol. %. The positive electrodes24may have an interparticle porosity84between the positive solid-state electroactive particles60and/or the solid-state electrolyte particles92that is greater than or equal to 0 vol. % to less than or equal to 50 vol. %, and in certain aspects, optionally greater than or equal to 2 vol. % to less than or equal to 20 vol. %.

Although not illustrated, in certain variations, the positive electrode24may further include one or more conductive additives and/or binder materials. For example, the positive solid-state electroactive particles60(and/or third plurality of solid-state electrolyte particles92) may be optionally intermingled with one or more electrically conductive materials (not shown) that provide an electron conduction path and/or at least one polymeric binder material (not shown) that improves the structural integrity of the positive electrode24.

The positive electrode24may include greater than or equal to 0 wt. % to less than or equal to about 30 wt. %, and in certain aspects, optionally greater than or equal to about 2 wt. % to less than or equal to about 10 wt. %, of the one or more electrically conductive additives; and greater than or equal to 0 wt. % to less than or equal to about 20 wt. %, and in certain aspects, optionally greater than or equal to about 1 wt. % to less than or equal to about 10 wt. %, of the one or more binders.

The positive electrode24may include greater than or equal to 0 wt. % to less than or equal to 30 wt. %, and in certain aspects, optionally greater than or equal to 2 wt. % to less than or equal to 10 wt. %, of the one or more electrically conductive additives; and greater than or equal to 0 wt. % to less than or equal to 20 wt. %, and in certain aspects, optionally greater than or equal to 1 wt. % to less than or equal to 10 wt. %, of the one or more binders.

As illustrated inFIG.1A, direct contact between the solid-state electroactive particles50,60and/or the solid-state electrolyte particles30,90,92may be much lower than the contact between a liquid electrolyte and solid-state electroactive particles in comparable non-solid-state batteries. For example, as illustrated inFIG.1A, a battery20in green form may have an overall interparticle porosity that is greater than or equal to about 10 vol. % to less than or equal to about 40 vol. %. A battery20in green form may have an overall interparticle porosity that is greater than or equal to 10 vol. % to less than or equal to 40 vol. %. In certain variations, a polymeric gel electrolyte (e.g., a semi-solid electrolyte) may be disposed within a solid-state battery so as to wet interfaces and/or fill void spaces between the solid-state electrolyte particles and/or the solid-state active material particles. However, such polymeric gel electrolytes often do not enable fast lithium-ion intercalation and deintercalation, particularly in the instance of graphite-containing negative electrodes.

The present disclosure provides a polymeric gel electrolyte system100. A gel electrolyte system has a viscosity greater than or equal to about 10,000 centipoise. In various aspects, the polymeric gel system100includes non-lithium cations that enable pre-intercalation prior to lithiation, thereby improving power performance, for example at 10° C. For example, as illustrated inFIG.1B, the polymeric gel electrolyte system100may be disposed within the battery20between the solid-state electrolyte particles30,90,92and/or the solid-state electroactive particles50,60, so as to, for example only, reduce interparticle porosity80,82,84and improve ionic contact and/or enable higher thermal stability. In certain variations, the battery20may include greater than or equal to about 0.5 wt. % to less than or equal to about 50 wt. %, and in certain aspects, optionally greater than or equal to about 5 wt. % to less than or equal to about 35 wt. %, of the polymeric gel electrolyte system100. The battery20may include greater than or equal to 0.5 wt. % to less than or equal to 50 wt. %, and in certain aspects, optionally greater than or equal to 5 wt. % to less than or equal to 35 wt. %, of the polymeric gel electrolyte system100.

Although it appears that there are no pores or voids remaining in the illustrated figure, some porosity may remain between adjacent particles (including, for example only, between the solid-state electroactive particles50and/or the solid-state electrolyte particles90and/or the solid-state electrolyte particles30, and between the solid-state electroactive particles60and/or the solid-state electrolyte particles92and/or the solid-state electrolyte particles30) depending on the penetration of the polymeric gel electrolyte system100. For example, a battery20including the polymeric gel electrolyte system100may have a porosity less than or equal to about 50 vol. %, and in certain aspects, optionally less than or equal to about 30 vol. %. A battery20including the polymeric gel electrolyte system100may have a porosity less than or equal to 50 vol. %, and in certain aspects, optionally less than or equal to 30 vol. %. A battery20including the polymeric gel electrolyte system100may have a porosity less than or equal to about 50 vol. %, and in certain aspects, optionally less than or equal to about 30 vol. %. A battery20including the polymeric gel electrolyte system100may have a porosity less than or equal to 50 vol. %, and in certain aspects, optionally less than or equal to 30 vol. %.

In various aspects, the polymeric gel electrolyte system100includes a non-volatile gel and a non-lithium salt. For example, the polymeric gel electrolyte system100may include greater than or equal to about 50 wt. % to less than or equal to about 99.9 wt. %, and in certain aspects, optionally greater than or equal to about 80 wt. % to less than or equal to about 99.5 wt. %, of the non-volatile gel, and greater than or equal to about 0.1 wt. % to less than or equal to about 20 wt. %, and in certain aspects, optionally greater than or equal to about 0.5 wt. % to less than or equal to about 10 wt. %, of the non-lithium salt. The polymeric gel electrolyte system100may include greater than or equal to 50 wt. % to less than or equal to 99.9 wt. %, and in certain aspects, optionally greater than or equal to 80 wt. % to less than or equal to 99.5 wt. %, of the non-volatile gel, and greater than or equal to 0.1 wt. % to less than or equal to 20 wt. %, and in certain aspects, optionally greater than or equal to 0.5 wt. % to less than or equal to 10 wt. %, of the non-lithium salt.

A non-volatile is one having a low vapor pressure, for example, less than or equal to about 10 mmHg at 25° C. In various aspects, the non-volatile gel may include greater than or equal to 0 wt. % to less than or equal to about 50 wt. %, and in certain aspects, optionally, greater than or equal to about 1 wt. % to less than or equal to about 20 wt. %, of the polymeric host, and greater than or equal to about 5 wt. % to less than or equal to about 100 wt. %, and in certain aspects, optionally greater than or equal to about 80 wt. % to less than or equal to about 90 wt. %, of the liquid electrolyte. The non-volatile gel may include greater than or equal to 0 wt. % to less than or equal to 50 wt. %, and in certain aspects, optionally, greater than or equal to 1 wt. % to less than or equal to 20 wt. %, of the polymeric host, and greater than or equal to 5 wt. % to less than or equal to 100 wt. %, and in certain aspects, optionally greater than or equal to 80 wt. % to less than or equal to 90 wt. %, of the liquid electrolyte.

In certain variations, the non-volatile gel further includes an additive. For example, the non-volatile gel may include greater than or equal to 0 wt. % to less than or equal to about 20 wt. %, and in certain aspects, optionally, greater than or equal to about 0.1 wt. % to less than or equal to about 10 wt. %, of the additive. The non-volatile gel may include greater than or equal to 0 wt. % to less than or equal to 20 wt. %, and in certain aspects, optionally, greater than or equal to 0.1 wt. % to less than or equal to 10 wt. %, of the additive.

The liquid electrolyte may include a lithium salt and a solvent. For example, the liquid electrolyte may include greater than or equal to about 5 wt. % to less than or equal to about 70 wt. %, and in certain aspects, optionally greater than or equal to about 10 wt. % to less than or equal to about 50 wt. %, of the lithium salt, and greater than or equal to about 30 wt. % to less than or equal to about 95 wt. %, and in certain aspects, optionally greater than or equal to about 50 wt. % to less than or equal to about 90 wt. %, of the solvent. The liquid electrolyte may include greater than or equal to 5 wt. % to less than or equal to 70 wt. %, and in certain aspects, optionally greater than or equal to 10 wt. % to less than or equal to 50 wt. %, of the lithium salt, and greater than or equal to 30 wt. % to less than or equal to 95 wt. %, and in certain aspects, optionally greater than or equal to 50 wt. % to less than or equal to 90 wt. %, of the solvent.

The additive may be selected to encourage formation of a robust and thin solid-electrolyte interface (SEI) layer on or adjacent to one or more surfaces of the negative electrode22, for example on the surface of the negative electrode22opposing the electrolyte layer26. In various aspects, the first additive may include, for example, unsaturated carbon bond containing compounds (such as, vinylene carbonate (VC), vinyl ethylene carbonate (VEC), and the like), sulfur-containing compounds (such as, ethylene sulfite (ES), propylene sulfite (PyS), and the like), halogen-containing compounds (such as, fluoroethylene carbonate (FEC), chloro-ethylene carbonate (Cl-EC), and the like), methyl substituted glycolide derivatives, maleimide (MI) additives, additives or compounds containing electron withdrawing groups, and combinations thereof. For example, the additive may be selected from the group consisting of: vinylene carbonate (VC), fluoroethylene carbonate (FEC), vinylethylene carbonate (VEC), butylene carbonate (BC), ethylene sulfite (ES), propylene sulfite (PS), and combinations thereof.

The non-lithium salt should be soluble in the solvent (e.g., ethylene carbonate (EC), propylene carbonate (PC), gamma-butyrolactone (GBL), tetraethyl phosphate (TEP), and/or fluoroethylene carbonate (FEC)) of the liquid electrolyte. The non-lithium salt includes a non-lithium cation and an anion. The non-lithium cation should have an ion radius that is comparable with or larger than the radius of a lithium ion (Lit).

For example, the non-lithium cation may have a ion radius that is greater than or equal to about 80% to less than or equal to about 250%, optionally greater than or equal to about 100% to less than or equal to about 250%, optionally greater than or equal to about 110% to less than or equal to about 250%, optionally greater than or equal to about 120% to less than or equal to about 250%, optionally greater than or equal to about 130% to less than or equal to about 250%, optionally greater than or equal to about 140% to less than or equal to about 250%, optionally greater than or equal to about 150% to less than or equal to about 250%, optionally greater than or equal to about 160% to less than or equal to about 250%, optionally greater than or equal to about 170% to less than or equal to about 250%, optionally greater than or equal to about 180% to less than or equal to about 250%, optionally greater than or equal to about 190% to less than or equal to about 250%, optionally greater than or equal to about 200% to less than or equal to about 250%, optionally greater than or equal to about 210% to less than or equal to about 250%, optionally greater than or equal to about 220% to less than or equal to about 250%, optionally greater than or equal to about 230% to less than or equal to about 250%, and in certain aspects, optionally greater than or equal to about 240% to less than or equal to about 250%, of a ion radius of a lithium ion.

The non-lithium cation may have a ion radius that is greater than or equal to 80% to less than or equal to 250%, optionally greater than or equal to 100% to less than or equal to 250%, optionally greater than or equal to 110% to less than or equal to 250%, optionally greater than or equal to 120% to less than or equal to 250%, optionally greater than or equal to 130% to less than or equal to 250%, optionally greater than or equal to 140% to less than or equal to 250%, optionally greater than or equal to 150% to less than or equal to 250%, optionally greater than or equal to 160% to less than or equal to 250%, optionally greater than or equal to 170% to less than or equal to 250%, optionally greater than or equal to 180% to less than or equal to 250%, optionally greater than or equal to 190% to less than or equal to 250%, optionally greater than or equal to 200% to less than or equal to 250%, optionally greater than or equal to 210% to less than or equal to 250%, optionally greater than or equal to 220% to less than or equal to 250%, optionally greater than or equal to 230% to less than or equal to 250%, and in certain aspects, optionally greater than or equal to 240% to less than or equal to 250%, of a ion radius of a lithium ion.

In certain variations, the non-lithium cation may be selected from the group consisting of: sodium (Na+), calcium (Ca2+), magnesium (Mg2+), potassium (K+), aluminum (Al3+), iron (Fe2+), manganese (Mn2+), strontium (Sr2+), zinc (Zn2+), and combinations thereof. A lithium ion (Lit) may have a radius (pm) of about 76. A magnesium ion (Mg2) may have a radius (pm) of about 72. A calcium ion (Ca2) may have a radius (pm) of about 100. A potassium ion (K+) may have a radius (pm) of about 138. A lithium ion (Lit) may have a radius (pm) of 76. A magnesium ion (Mg2+) may have a radius (pm) of 72. A calcium ion (Ca2) may have a radius (pm) of 100. A potassium ion (K+) may have a radius (pm) of 138.

The anion may be the same or different from the anion of the liquid electrolyte. For example, in certain variations, the anion may be selected from the group consisting of: bis-trifluoromethanesulfonimide (TFSI−), bis(fluorosulfonyl)imide (FSI−), bis(pentafluoroethanesulfonyl)imide (BETI−), trifluoromethyl sulfonate (OTf−), tetrafluoroborate (BF4−), hexafluorophosphate(PF6−), nitrate (NO3−), chloride(Cl−), bromide (Br−), and combinations thereof. Thus, the non-lithium salt may be selected from the group consisting of: magnesium bis(trifluoromethanesulfonyl)imide (Mg(TFSI)2), calcium bis(trifluoromethanesulfonyl)imide (Ca(TFSI)2), potassium bis(trifluoromethanesulfonyl)imide (KTFSI), sodium nitrate (NaNO3), sodium hexafluorophosphate (NaPF6), and combinations thereof.

In each variation, the non-lithium cation is selected to pre-intercalate into the electroactive material (e.g., graphite) of the negative electrode22prior to lithiation, such that the non-lithium cation can serve as a pillar to facilitate subsequent lithium transportation. The non-lithium cation may pre-intercalate into the electroactive material of the negative electrode22prior to lithiation as a result of chemical potential differentiation. That is, the electrochemical potential of the non-lithium cations intercalation into the electroactive material of the negative electrode22is higher than the electrochemical potential of lithium ions intercalation into the electroactive material of the negative electrode22. In certain variations, the potential difference for the non-lithium cation and the lithium ions may be greater than or equal to about 0.1 V to less than or equal to about 3V. The potential difference for the non-lithium cation and the lithium ions may be greater than or equal to 0.1 V to less than or equal to 3V.

FIG.1Cis a schematic illustration of a two-dimensional electroactive material (e.g., graphite)50in contact with a polymeric gel electrolyte system100. As illustrated, during battery20formation, non-lithium cations102from the polymeric gel electrolyte system100intercalates and expands layers of the two-dimensional electroactive material50, and during subsequent charging110and discharging120events lithium ions104moves into and out of the electroactive material, in relation to the non-lithium cations. Intercalation of the non-lithium cations102may increases d-spacing, also referred to as interlayer spacing, of the two-dimensional electroactive material50, so as to broaden the passageways for lithium ions, thereby improving lithium ion transportation.

An exemplary and schematic illustration of another solid-state electrochemical cell unit200that cycles lithium ions is shown inFIG.2. Like battery20, the battery220includes a negative electrode (i.e., anode)222, a first bipolar current collector232positioned at or near a first side of the negative electrode222, a positive electrode (i.e., cathode)224, a second bipolar current collector234positioned at or near a first side of the positive electrode224, and an electrolyte layer226disposed between a second side of the negative electrode222and a second side of the positive electrode224, where the second side of the negative electrode222is substantially parallel with the first side of the negative electrode222and the second side of the positive electrode224is substantially parallel with the first side of the positive electrode224.

Like the negative electrode22illustrated inFIGS.1A and1B, the negative electrode222may include a plurality of negative solid-state electroactive particles250mixed with an optional first plurality of solid-state electrolyte particles290. The negative electrode222may further include a first polymeric gel electrolyte system282that at least partially fills void spaces between the negative solid-state electroactive particles250and/or the optional solid-state electrolyte particles290.

Like the positive electrode24illustrated inFIGS.1A and1B, the positive electrode224may include a plurality of positive solid-state electroactive particles260mixed with an optional second plurality of solid-state electrolyte particles292. The positive electrode224may further include a second polymeric gel system284that at least partially fills void spaces between the positive solid-state electroactive particles260and/or the optional solid-state electrolyte particles292. The second polymeric gel system284may be the same or different from the first polymeric gel system282. Like the polymeric gel electrolyte system illustrated inFIGS.1A and1B, the first and second polymeric gel systems282,284illustrated inFIG.2include a non-volatile gel and a non-lithium salt.

The electrolyte layer226may be a separating layer that physically separates the negative electrode222from the positive electrode224. The electrolyte layer226may be a free-standing membrane280defined by a third polymeric gel electrolyte system comprising a non-volatile gel and a non-lithium salt similar to the polymeric gel electrolyte system illustrated inFIGS.1A and1B. In certain variations, the free-standing membrane280may have a thickness greater than or equal to about 5 μm to less than or equal to about 1,000 μm, and in certain aspects, optionally greater than or equal to about 2 μm to less than or equal to about 100 μm. The free-standing membrane280may have a thickness greater than or equal to 5 μm to less than or equal to 1,000 μm, and in certain aspects, optionally greater than or equal to 2 μm to less than or equal to 100 μm.

Although not illustrated, the skilled artisan will recognize that, in certain variations, the negative electrode222may be free of a first polymeric gel electrolyte system282and/or the positive electrode224may be free of a second polymeric gel electrolyte system284. Similarly, considering the teachings ofFIGS.1A and1B, although not illustrated, the skilled artisan will recognize that, in certain variations, the negative electrode22, the positive electrode24, and/or the electrolyte layer26may be free of the polymeric gel electrolyte system100. That is, in the instance ofFIG.1B, one of the negative electrode22, the positive electrode24, and/or the electrolyte layer26may include polymeric gel electrolyte system100.

In various aspects, the present disclosure provides methods for fabricating a battery including a gel electrolyte system, such as the battery20illustrated inFIG.1Band/or the battery200illustrated inFIG.2.

For example, in certain variations, the present disclosure contemplates a method of making a first electrode, where the method generally includes contacting a first precursor liquid with a first or negative electrode precursor in the form of a first or negative electroactive material layer, and concurrently or simultaneously, contacting a second precursor liquid with a second or positive electrode precursor in the form of a second or positive electroactive material layer. The first precursor liquid may be the same as or different from the second precursor liquid. In such instances, the method further includes drying or reacting (e.g., cross-linking) the first precursor liquid to form a gel-assisted first or negative electrode that includes a first polymeric gel electrolyte, and concurrently or simultaneously, drying or reacting (e.g., cross-linking) the second precursor liquid to form a gel-assisted second or positive electrode that includes a second polymeric gel electrolyte

The method may also include, concurrently or simultaneously with the first and/or second contacts, contacting a third precursor liquid with a precursor electrolyte layer including a plurality of solid-state electrolyte particles and drying or reacting (e.g., cross-linking) the third precursor liquid to form a gel-assisted electrolyte layer including a third polymeric gel electrolyte. In other variations, the method may further include, concurrently or simultaneously with the first and/or second contacts, forming a free-standing membrane defined by a polymeric gel (such as formed from the third precursor liquid). The third precursor liquid may be the same as or different from the first precursor liquid and/or the second precursor liquid. The first, second, and third precursor liquids include a non-volatile gel and a non-lithium salt, such as detailed above in the context ofFIG.1B.

In each instance, the method includes substantially aligning and/or stacking the first or negative electrolyte layer, the second or positive electrolyte layer, and the gel-assisted electrolyte layer and/or free-standing membrane defined by the polymeric gel. Although the above discussion describes a single negative electrode, a single positive electrode, and a single electrolyte layer, the skilled artisan will recognize that the current teachings apply to various other configurations, including those having one or more anodes, one or more cathodes, and one or more electrolyte layers, as well as various current collectors and current collector films with electroactive particle layers disposed on or adjacent to or embedded within one or more surfaces thereof.

In other variations, the present disclosure contemplates a method of making a first electrode, where the method generally includes an in situ process that includes contacting a polymeric precursor and a battery having an interparticle porosity (for example, the battery20illustrated inFIG.1A). The contacting may include adding one or more drops of the polymeric precursor to the battery. The method further includes drying or reacting (e.g., cross-linking) the polymeric precursor to form a polymeric gel electrolyte system, like the polymeric gel electrolyte system100illustrated inFIG.1B. In certain variations, the method may include preparing the polymeric precursor. Preparing the polymeric precursor may include contacting a non-volatile gel and a non-lithium salt, such as detailed above in the context ofFIG.1B.

Certain features of the current technology are further illustrated in the following non-limiting examples.

Example battery cells may be prepared in accordance with various aspects of the present disclosure. For example, the example battery cells may a polymeric gel electrolyte system including a non-volatile gel and a non-lithium salt. A first example battery cell310may include a first polymeric gel electrolyte system312. The first polymeric gel electrolyte system312may include about 1 wt. % of magnesium bis(trifluoromethanesulfonyl)imide (Mg(TFSI)2) as the non-lithium salt. A second example battery cell320may include a second polymeric gel electrolyte system322. The second polymeric gel electrolyte system322may include about 1 wt. % of calcium bis(trifluoromethanesulfonyl)imide (Ca(TFSI)2). The first and second polymeric gel electrolyte systems312,322may each include poly(vinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) as the polymeric host and a liquid electrolyte including 0.4 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and 0.4 M lithium tetrafluoroborate (LiBF4) in a solvent mixture. The solvent mixture (e.g., 4:6 v/v) may include ethylene carbonate (EC) and gamma-butyrolactone (GBL).

Like battery20illustrated inFIGS.1A and1B, the first and second example battery cells310,320include a first or negative electrode including a plurality of negative solid-state electroactive material particles, and optionally, a first plurality of solid-state electrolyte particles, disposed on or adjacent to a first surface of a first bipolar current collector. The example battery cells310,320may further include a second or positive electrode parallel with the negative electrode. The positive electrode may include a plurality of positive solid-state electroactive material particles, and optionally, a second plurality of solid-state electrolyte particles, disposed on or adjacent to a first surface of a second bipolar current collector. The example battery cells310,320may further include a solid-electrolyte layer disposed between and physically separating the negative electrode and the positive electrode. More specifically, the solid-electrolyte layer may separate the plurality of negative solid-state electroactive material particles (and the optional first plurality of solid-state electrolyte particles) and the plurality of positive solid-state electroactive material particles (and the optional second plurality of solid-state electrolyte particles). The negative electrodes and/or positive electrodes and/or solid-electrolyte layer may include polymeric gel electrolyte systems312,322, in accordance with various aspects of the present disclosure.

FIG.3Ais a graphical illustration demonstrating rate capability of the example battery cells310,320including polymeric gel electrolyte systems312,322in accordance with various aspects of the present disclosure and comparable battery cell330having the same configuration as the example battery cells310,320, but not including a polymeric gel electrolyte system. The x-axis300represents discharge rate (e.g., c-rate). C-rate is a measure of the rate at which a battery is discharged relative to its maximum capacity. For example, a 1 C rate indicates that the discharge current will discharge the entire battery for 1 hour. The y-axis302represents capacity retention (%). As illustrated, the example battery cells310,320has improved long-term and high-power performance.

FIG.3Bis a graphical illustration demonstrating cell discharge of the example battery cells310,320including polymeric gel electrolyte systems312,322in accordance with various aspects of the present disclosure and comparable battery cell330having the same configuration as the example battery cells310,320, but not including a polymeric gel electrolyte system. The x-axis304represents capacity retention (%). The y-axis306represents voltage (V). Line340is the gel electrolyte discharge at 1 C rate. Line310is the discharge curve for example battery cell310at 10 C rate. Line320is the discharge curve for example battery320at 10 C rate. Line330is the discharge curve for the comparative battery330at 10 C rate. As illustrated, the example battery cells310,320have improved high power performance as compared to the comparative battery330, especially at 10 C rate.