SOLID-STATE ELECTROLYTE MATERIALS FOR ALL-SOLID-STATE BATTERIES

The present disclosure provides an all-solid-state electrochemical battery that includes a positive electrode, a negative electrode, and a solid-state electrolyte layer disposed between and separating the positive electrode and the negative electrode. The positive electrode includes a positive electroactive material and a solid-state electrolyte material. The solid-state electrolyte material may be represented by Li3AB6, where A is selected from the group consisting of: yttrium (Y), indium (In), scandium (Sc), erbium (Er), and combinations thereof, and B is selected from the group consisting of: chloride (Cl), bromide (Br), ClxBr(x−1) (where 0<x<1), and combinations thereof. In certain variations, the positive electroactive material includes a nickel-rich electroactive material, and the solid state electrolyte layer includes a sulfide-based electrolyte material. The solid-state electrolyte layer can also include the solid-state electrolyte material may be represented by Li3AB6.

INTRODUCTION

Advanced energy storage devices and systems are in demand to satisfy energy and/or power requirements for a variety of products, including automotive products such as start-stop systems (e.g., 12V start-stop systems), battery-assisted systems, hybrid electric vehicles (“HEVs”), and electric vehicles (“EVs”). Typical lithium-ion batteries include at least two electrodes and an electrolyte and/or separator. One of the two electrodes may serve as a positive electrode or cathode and the other electrode may serve as a negative electrode or anode. 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 solid and/or liquid form and/or a hybrid thereof. In instances of solid-state batteries, which include solid-state electrodes and a solid-state electrolyte, the solid-state electrolyte may physically separate the electrodes so that a distinct separator is not required.

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, 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. In various aspects, positive electrodes include nickel-rich electroactive materials (e.g., greater than or equal to about 0.6 mole fraction on transition metal lattice), such as NMC (LiNi1−x−yCoxMnyO2) (where 0.10≤x≤0.33, 0.10≤y≤0.33) or NCMA (LiNi1−x−y−zCoxMnyAlzO2) (where 0.02≤x≤0.20, 0.01≤y≤0.12, 0.01≤z≤0.08), which are capable of providing improved capacity capability (e.g., greater than 200 mAh/g) while allowing for additional lithium extraction without compromising the structural stability of the positive electrode. Such materials, however, often have poor interfacial compatibility or stability with solid-state electrolytes, and in particular, sulfide electrolyte. Hot pressing processes can be used during the formation of solid-state electrolyte layers, and also, solid-state electrodes. However, solid-state electrolytes, and in particular, sulfide electrolyte, often negatively react with nickel-rich electroactive materials at elevated temperatures. Accordingly, it would be desirable to develop improved materials, and methods of making and using the same, that can address these challenges.

SUMMARY

The present disclosure relates to all-solid-state electrochemical cells having reduced porosity and including solid-state electrolyte materials represented by Li3AB6, where A is yttrium (Y), indium (In), scandium (Sc), or erbium (Er), and B is chloride (Cl), bromide (Br), and/or ClxBr(x−1), where 0<x<1, as well as methods of making and using the same.

In various aspects, the present disclosure provides an all-solid-state electrochemical battery that includes a positive electrode, a negative electrode, and a solid-state electrolyte layer disposed between and separating the positive electrode and the negative electrode. The positive electrode includes a positive electroactive material and a solid-state electrolyte material. The solid-state electrolyte material may be represented by Li3AB6, where A is selected from the group consisting of: yttrium (Y), indium (In), scandium (Sc), erbium (Er), and combinations thereof, and B is selected from the group consisting of: chloride (Cl), bromide (Br), ClxBr(x−1)(where 0<x<1), and combinations thereof. The negative electrode may include a negative electroactive material.

In one aspect, the positive electrode may have a porosity less than or equal to about 15 vol. %.

In one aspect, the positive electroactive material may be selected from the group consisting of: NMC (LiNi1−x−yCoxMnyO2) (where 0.10≤x≤0.33, 0.10≤y≤0.33), NCMA (LiNi1−x−y−zCoxMnyAlzO2) (where 0.02≤x≤0.20, 0.01≤y≤0.12, 0.01≤z≤0.08), and combinations thereof.

In one aspect, the positive electrode may have a positive electroactive material loading greater than or equal to about 70 wt. %,

In one aspect, the solid-state electrolyte layer may have a porosity less than or equal to about 15 vol. %, and the solid-state electrolyte layer may also include the solid-state electrolyte material represented by Li3AB6, where A is selected from the group consisting of: yttrium (Y), indium (In), scandium (Sc), erbium (Er), and combinations thereof, and B is selected from the group consisting of: chloride (Cl), bromide (Br), ClxBr(x−1)(where 0<x<1), and combinations thereof.

In one aspect, the negative electrode may include a lithium metal foil.

In one aspect, the negative electrode may include a negative electroactive material selected from the group consisting of: lithium, silicon, silicon oxide, graphite, Li4+xTi5O12(where 0≤x≤3), and combinations thereof.

In various aspects, the present disclosure may provide an all-solid-state electrochemical battery that includes a positive electrode, a negative electrode, and a solid-state electrolyte layer disposed between and separating the positive electrode and the negative electrode. The positive electrode may include a positive electroactive material. The negative electrode may include a negative electroactive material. The solid-state electrolyte layer may include a solid-state electrolyte material represented by Li3AB6, where A is selected from the group consisting of: yttrium (Y), indium (In), scandium (Sc), erbium (Er), and combinations thereof, and B is selected from the group consisting of: chloride (Cl), bromide (Br), ClxBr(x−1)(where 0<x<1), and combinations thereof.

In one aspect, the solid-state electrolyte layer may have a porosity less than or equal to about 15 vol. %.

In one aspect, the positive electroactive material may be selected from the group consisting of: NMC (LiNi1−x−yCoxMnyO2) (where 0.10≤x≤0.33, 0.10≤y≤0.33), NCMA (LiNi1−x−y−zCoxMnyAlzO2) (where 0.02≤x≤0.20, 0.01≤y≤0.12, 0.01≤z≤0.08), and combinations thereof.

In one aspect, the positive electrode may also include the solid-state electrolyte material represented by Li3AB6, where A is selected from the group consisting of: yttrium (Y), indium (In), scandium (Sc), erbium (Er), and combinations thereof, and B is selected from the group consisting of: chloride (Cl), bromide (Br), ClxBr(x−1)(where 0<x<1), and combinations thereof.

In one aspect, the solid-state electrolyte material may be a first solid-state electrolyte material and the solid-state electrolyte layer may further include a second solid-state electrolyte material selected form the group consisting of: sulfide-based solid-state electrolyte material, halide-doped sulfide-based solid-state electrolyte material, oxysulfide solid-state electrolyte material, halide-doped oxysulfide solid-state electrolyte material, and combinations thereof.

In one aspect, the positive electrode may have a porosity less than or equal to about 15 vol. %.

In various aspects, the present disclosure may provide a method for preparing an all-solid-state battery. The method may include preparing a positive electrode having a porosity less than or equal to about 15 vol. % and a positive solid-state electroactive material loading greater than or equal to about 70 wt. % by contacting a plurality of positive solid-state electroactive particles and a plurality of solid-state electrolyte particles to form an admixture, and applying a pressure to the admixture at a temperature greater than or equal to about 200° C. to less than or equal to about 250° C. for a period greater than or equal to about 0.1 minutes to less than or equal to about 10 minutes to form the positive electrode. The solid-state electrolyte particles may include a solid-state electrolyte material represented by Li3AB6, where A is selected from the group consisting of: yttrium (Y), indium (In), scandium (Sc), erbium (Er), and combinations thereof, and B is selected from the group consisting of: chloride (Cl), bromide (Br), ClxBr(x−1)(where 0<x<1), and combinations thereof. The pressure may be greater than or equal to about 75 MPa to less than or equal to about 450 MPa.

In one aspect, the plurality of solid-state electrolyte particles may be a first plurality of solid-state electrolyte particle, the pressure is a first pressure, the temperature is a first temperature, the period is a first period, and the method may further include preparing a solid-state electrolyte layer. Preparing the solid-state electrolyte layer may include applying a second pressure to a second plurality of solid-state electrolyte particles at a second temperature greater than or equal to about 200° C. to less than or equal to about 250° C. for a second period greater than or equal to about 0.1 minute to less than or equal to about 10 minutes to form the solid-state electrolyte layer. The second pressure may be greater than or equal to about 75 MPa to less than or equal to about 450 MPa. The preparing of the solid-state electrolyte layer may occur concurrently or consecutively with the preparing of the positive electrode.

In one aspect, the solid-state electrolyte layer may be prepared concurrently with the positive electrode, and the method may further include disposing the second plurality of solid-state electrolyte particles adjacent to the admixture.

In one aspect, the method may further include disposing a lithium metal foil on or adjacent to an exposed surface of the solid-state electrolyte layer.

In one aspect, the admixture may be a first admixture and the method may further include disposing a second admixture on or adjacent to an exposed surface defined by the second plurality of solid-state electrolyte particles. The second admixture may include a plurality of negative solid-state electroactive particles and a third plurality of solid-state electrolyte particle.

In one aspect, the second plurality of solid-state electrolyte particles may be the same as the first plurality of solid-state electrolyte particles.

In one aspect, the solid-state electrolyte material may be a first solid-state electrolyte material and the second plurality of solid-state electrolyte particles may include a second solid-state electrolyte material selected form the group consisting of: sulfide-based solid-state electrolyte material, halide-doped sulfide-based solid-state electrolyte material, oxysulfide solid-state electrolyte material, halide-doped oxysulfide solid-state electrolyte material, and combinations thereof.

DETAILED DESCRIPTION

The present technology relates to all-solid-state electrochemical cells having reduced porosity and including solid-state electrolyte materials represented by Li3AB6, where A is yttrium (Y), indium (In), scandium (Sc), or erbium (Er), and B is chloride (Cl), bromide (Br), and/or ClxBr(x−1), where 0<x<1, as well as methods of making and using the same. Such cells 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.

In certain variations, batteries including all-solid-state electrochemical cells that are prepared in accordance with various aspects of the present disclosure may have a bipolar stacking design comprising a plurality of bipolar electrodes where a first mixture of electroactive material particles (and optional solid-state electrolyte particles) is disposed on a first side of a current collector, and a second mixture of electroactive material particles (and optional solid-state electrolyte particles) is disposed on a second side of a current collector that is parallel with the first side. The first mixture may include, as the electroactive material particles, cathode material particles having one or more coatings. The second mixture may include, as the electroactive material particles, anode material particles. The solid-state electrolyte particles in each instance may be the same or different.

In other variations, batteries including all-solid-state electrochemical cells that are prepared in accordance with various aspects of the present disclosure may have a monopolar stacking design comprising a plurality of monopolar electrodes where a first mixture of electroactive material particles (and optional solid-state electrolyte particles) is disposed on both a first side and a second side of a first current collector, wherein the first and second sides of the first current collector are substantially parallel, and a second mixture of electroactive material particles (and optional solid-state electrolyte particles) is disposed on both a first side and a second side of a second current collector, where the first and second sides of the second current collector are substantially parallel. The first mixture may include, as the electroactive material particles, cathode material particles having one or more coating. The second mixture may include, as electroactive material particles, anode material particles. The solid-state electrolyte particles in each instance may be the same or different. In certain variations, the batteries may include a mixture of combination of bipolar and monopolar stacking designs.

An exemplary and schematic illustration of a solid-state electrochemical cell (also referred to as a “all-solid-state battery” and/or “solid-state battery” and/or “battery”)20that cycles lithium ions is shown inFIG.1. The battery20includes a negative electrode (i.e., anode)22, a positive electrode (i.e., cathode)24, and an electrolyte layer26that occupies a space defined between the electrodes. The electrolyte layer26is a 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. The second plurality of solid-state electrolyte particles90may define an anolyte. The third plurality of solid-state electrolyte particles92may define a catholyte.

A first current collector32may be positioned at or near the negative electrode22. In certain instances, the first current collector32together with the negative electrode22may be referred to as a negative electrode assembly. The first current collector32may be a metal foil, metal grid or screen, or expanded metal comprising copper, stainless steel, nickel, iron, titanium, or any other appropriate electrically conductive material known to those of skill in the art. In certain variations, the first current collector32may be coated foil having improved corrosion resistance, such as graphene or carbon coated stainless steel foil. The first current collector32may have an average thickness greater than or equal to about or exactly 2 μm to less than or equal to about or exactly 30 μm.

A second current collector34may be positioned at or near the positive electrode24. In certain instances, the second current collector34together with the positive electrode24may be referred to as a positive electrode assembly. The second current collector34may be a metal foil, metal grid or screen, or expanded metal comprising stainless steel, aluminum, nickel, iron, titanium, or any other appropriate electrically conductive material known to those of skill in the art. In certain variations, the second current collector34may be coated foil having improved corrosion resistance, such as graphene or carbon coated stainless steel foil. The second current collector34may have an average thickness greater than or equal to about or exactly 2 μm to less than or equal to about or exactly 30 μm.

Although not illustrated, the skilled artisan will recognize that in certain variations, the first current collector32may be a first bipolar current collector and/or the second current collector34may be a second bipolar current collector. For example, the first bipolar current collector32and/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 collector32includes 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), or nickel-stainless steel (Ni—SS). In certain variations, the first bipolar current collector32and/or second bipolar current collectors34may be pre-coated, such as graphene or carbon-coated aluminum current collectors.

The first current collector32and the second current collector34may be the same or different. In each instance, however, the first current collector32and the second electrode current collector34respectively collect and move free electrons to and from an external circuit40. For example, an interruptible external circuit40and a load device42may connect the negative electrode22(through the first current collector32) and the positive electrode24(through the second current collector34). The battery20can generate an electric current (indicated by arrows inFIG.1) 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 circuit40towards the positive electrode24. Lithium ions, which are also produced at the negative electrode22, are concurrently transferred through the electrolyte layer26towards 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 towards the negative electrode22through the external circuit40, and the lithium ions, which move across the electrolyte layer26back towards 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 26 layer.

In many configurations, each of the first current collector32, the negative electrode22, the electrolyte layer26, the positive electrode24, and the second 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 application 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 toFIG.1, as introduced above, the electrolyte layer26provides 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 or exactly 0.02 μm to less than or equal to about or exactly 20 μm, optionally greater than or equal to about or exactly 0.1 μm to less than or equal to about or exactly 10 μm, and in certain aspects, optionally greater than or equal to about or exactly 0.1 μm to less than or equal to about or exactly 5 μm. For example, in certain variations, the solid-state electrolyte particles30may include sulfide-based particles. In other variations, the solid-state electrolyte particles30may include oxide-based solid-state particles, metal-doped or aliovalent-substituted oxide solid-state particles, nitride-based solid-state particles sulfide-based particles, hydride-based particles, halide-based particles, borate-based solid-state particles, and/or other solid-state electrolyte particles having a low grain-boundary resistance (e.g., less than or equal to about or exactly 20 ohms at about or exactly 25° C.).

In certain variations, the sulfide-based particles may include oxysulfide-based electrolyte materials. The sulfide-based particles may include oxysulfide-based electrolyte materials may include lithium phosphorus (oxy)sulfide, sodium phosphorus (oxy)sulfide, lithium boron (oxy)sulfide, sodium boron (oxy)sulfide, lithium boron phosphorous oxysulfide, sodium boron phosphorous oxysulfide, lithium silicon (oxy)sulfide, sodium silicon (oxy)sulfide, lithium germanium (oxy)sulfide, sodium germanium (oxy)sulfide, lithium arsenic (oxy)sulfide, sodium arsenic (oxy)sulfide, lithium selenium (oxy)sulfide, sodium selenium (oxy)sulfide, lithium antimony (oxy)sulfide, and sodium antimony (oxy)sulfide. The term “(oxy)sulfide” refers to oxygen-free sulfide materials and oxygen-containing oxysulfide materials.

In still other variations, the solid-state electrolyte particles30may include, like the positive electrode24, one or more solid-state electrolyte materials represented by Li3AB6, where A is yttrium (Y), indium (In), scandium (Sc), or erbium (Er), and B is chloride (Cl), bromide (Br), and/or ClxBr(x−1), where 0<x<1. In such instances, for example as further detailed below, the electrolyte layer26may be prepared using a hot press process, such that the electrolyte layer26has an interparticle porosity less than or equal to about 20 vol. %, optionally less than or equal to about 15 vol. %, optionally less than or equal to about 10 vol. %, and in certain aspects, optionally less than or equal to about 5 vol. %, and an average thickness greater than or equal to about 10 μm to less than or equal to about 500 μm, and in certain aspects, optionally greater than or equal to about 10 μm to less than or equal to about 100 μm, optionally greater than or equal to about 10 μm to less than or equal to about 50 μm.

Although not illustrated, it should be recognized that in each variation the solid-state electrolyte layer26may further include a filler and/or a polymeric binder. For example, the solid-state electrolyte layer26may include greater than or equal to about 80 wt. % to less than or equal to about 100 wt. %, and in certain aspects, optionally greater than or equal to about 90 wt. % to less than or equal to about 100 wt. %, of the solid-state electrolyte particles30; greater than or equal to about 0 wt. % to less than or equal to about 20 wt. %, and in certain aspects, optionally greater than or equal to about 0 wt. % to less than or equal to about 10 wt. %, of the filler; and greater than or equal to about 0 wt. % to less than or equal to about 20 wt. %, and in certain aspects, optionally greater than or equal to about 0 wt. % to less than or equal to about 10 wt. %, of the polymeric binder.

Further still, although not illustrated, it should be recognized that in each variation the solid-state electrolyte layer26may further include a reinforcement material that can work to improve the fracture toughness of the solid-state electrolyte layer26without compromising its ionic conductivity, for example, as detailed in U.S. Pat. No. 10,734,673 (Filing Date: Jun. 23, 2017; Issue Date: Aug. 4, 2020; Title: “Ionically-Conductive Reinforced Glass Ceramic Separators/Solid Electrolytes”; Inventors: Thomas A. Yersak and James R. Salvador), herein incorporated by reference in its entirety.

With renewed reference toFIG.1, as illustrated, the negative electrode22may be defined by a plurality of the negative solid-state electroactive particles50. In certain instances, as illustrated, the negative electrode22may be a composite layer including, for example, the negative solid-state electroactive particles50and a 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 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 negative solid-state electroactive particles50; and greater than or equal to about 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. In each variation, the negative electrode22may have an average thickness greater than or equal to about 10 μm to less than or equal to about 500 μm, and in certain aspects, optionally greater than or equal to about 10 μm to less than or equal to about 100 μm.

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 same as or different from the third plurality of solid-state electrolyte particles92. In certain variations, the first plurality of solid-state electrolyte particles30may be the same as or different from the third plurality of solid-state electrolyte particles92.

The negative solid-state electroactive particles50may be formed from a lithium host material that is capable of functioning as a negative terminal of a lithium-ion battery. For example, in certain variations, the negative solid-state electroactive particles50may be lithium-based, for example, a lithium alloy (e.g., lithium titanate Li4+xTi5O12, where 0≤x≤3, such as Li4Ti5O12(LTO)). In other variations, the negative solid-state electroactive particles50may include, for example only, carbonaceous materials (such as, graphite, hard carbon, soft carbon, and the like) and/or metallic active materials (such as tin, aluminum, magnesium, germanium, and alloys thereof, and the like). In still other variations, the negative solid-state electroactive particles40may include, for example, metal oxides (such as Fe3O4, V2O5, SnO, Co3O4, NbOx, and the like) and/or metal sulfides (such as, FeS and the like). In further variations, the negative electrode22may include, for example, a silicon-based electroactive material (e.g., silicon containing binary and/r ternary alloys) and/or tin-containing alloys (such as Si, Li—Si, SiOx(where 0≤x≤2), Si—Sn, SiSnFe, SiSnAl, SiFeCo, SnO2, and the like).

In still further variations, the negative electrode22may include a combination of negative electroactive materials. For example, the negative electrode22may include a combination of the silicon-based electroactive material (i.e., first negative electroactive material) and one or more other negative electroactive materials. The one or more other negative electroactive materials may include, for example only, carbonaceous materials (such as, graphite, hard carbon, soft carbon, and the like) and/or metallic active materials (such as tin, aluminum, magnesium, germanium, and alloys thereof, and the like). Further still, although not illustrated, the skilled artisan will recognize that, in certain variations, the negative solid-state electroactive particles50(and also the optional second plurality of solid-state electrolyte particles90) may be replaced with a lithium metal foil having, for example, an average thickness greater than or equal to about 0 nm to less than or equal to about 500 μm, and in certain aspects, optionally greater than or equal to about 50 nm to less than or equal to about 50 μm

It should also be recognized, although not illustrated, that in certain variations, the negative solid-state electroactive material particles50(and the optional second plurality of solid-state electrolyte particles90) may be intermingled (e.g., slurry casted) with an electronically conductive material that provide an electron conductive path and/or a polymeric binder material that improves the structural integrity of the negative electrode22. For example, 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 0.5 wt. % to less than or equal to about 10 wt. %, of the electronically conducting material; 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 0.5 wt. % to less than or equal to about 10 wt. %, of the polymeric binder.

Electronically conducting materials may include carbon-based materials, powdered nickel or other metal particles, or a conductive polymer. Carbon-based materials may include, for example, particles of graphite, acetylene black (such as KETCHEN™ black or DENKA™ black), carbon nanofibers and nanotubes (e.g., single wall carbon nanotubes (SWCNT), multiwall carbon nanotubes (MWCNT)), graphene (e.g., graphene platelets (GNP), oxidized graphene platelets), conductive carbon blacks (such as, SuperP (SP)), and the like. Examples of a conductive polymer include polyaniline, polythiophene, polyacetylene, polypyrrole, and the like. The polymeric binder in the negative electrode may be the same as or different from the polymeric binder in the solid-state electrolyte layer26

As illustrated, the positive electrode24may be defined by a plurality of positive solid-state electroactive particles60. In certain instances, as illustrated, the positive electrode may be a composite layer including, for example, the positive solid-state electroactive particles60and a 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 about 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 solid-state electroactive particles60may include nickel-rich electroactive materials (e.g., greater than or equal to about 0.6 mole fraction on transition metal lattice), such as NMC (LiNi1−x−yCoxMnyO2) (where 0.10≤x≤0.33, 0.10≤y≤0.33) or NCMA (LiNi1−x−y−zCoxMnyAlzO2) (where 0.02≤x≤0.20, 0.01≤y≤0.12, 0.01≤z≤0.08). In other variations, the positive solid-state electroactive particles60may include one or more positive electroactive materials having a spinel structure (such as, lithium manganese oxide (Li(1+x)Mn2O4, where 0.1≤x≤1) (LMO) and/or lithium manganese nickel oxide (LiMn(2−x)NixO4, where 0≤x≤0.5) (LNMO) (e.g., LiMn1.5Ni0.5O4)); one or more materials with a layered structure (such as, lithium cobalt oxide (LiCoO2) (LCO)); and/or a lithium iron polyanion oxide with olivine structure (such as, lithium iron phosphate (LiFePO4) (LFP), lithium manganese-iron phosphate (LiMn2−xFexPO4, where 0<x<0.3) (LFMP), and/or lithium iron fluorophosphate (Li2FePO4F)). In still other variations, the positive solid-state electroactive particles60may include one or more positive electroactive materials selected from the group consisting of: LFP, LNMO, LMFP, LCO, FeS2, Li2S, TiS2, and combinations thereof. In further variations, the positive solid-state electroactive60may include a combination of any of the above listed materials positive solid-state electroactive materials.

The third plurality of solid-state electrolyte particles92may include one or more solid-state electrolyte materials represented by Li3AB6, where A is yttrium (Y), indium (In), scandium (Sc), or erbium (Er), and B is chloride (Cl), bromide (Br), and/or ClxBr(x−1), where 0<x<1. Such solid-state electrolyte materials are thermally stable (e.g., the material does not decompose into other compounds and/or react to form a passivating layer that prevents further reaction) when used in combination with nickel-rich electroactive materials at high or elevated temperatures (e.g., above about 100° C.), as compared to sulfide electrolyte material which often react with nickel-rich electroactive materials at high temperature because of the nickel-rich electroactive materials potential to oxidize the sulfide electrolyte in physical contact, especially at high charging potentials. In the current instance, because positive solid-state electroactive particles60and third plurality of solid-state electrolyte particles92are thermally stable, the positive electrode24may be formed, for example as further detailed below, using a hot press process, such that the positive electrode24has an interparticle porosity less than or equal to about 20 vol. %, and in certain aspects, optionally less than or equal to about 15 vol. %, and an average thickness greater than or equal to about 10 μm to less than or equal to about 500 μm, and in certain aspects, optionally greater than or equal to about 10 μm to less than or equal to about 100 μm. Because of the hot press process, the positive electrode24may have improved active material loading. For example, the positive electrode24may have a cathode active material (CAM) loading greater than or equal to about 70 wt. %, optionally greater than or equal to about 80 wt. %, and in certain aspects, optionally greater than or equal to about 90 wt. %.

Although not illustrated it should be recognized that, in certain variations, the positive solid-state electroactive material particles60and the third plurality of solid-state electrolyte particles92may be intermingled (e.g., slurry casted) with an electronically conductive material that provide an electron conductive path and/or a polymeric binder material that improves the structural integrity of the positive electrode24. For example, 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 0.5 wt. % to less than or equal to about 10 wt. %, of the electronically conducting material; 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 0.5 wt. % to less than or equal to about 10 wt. %, of the polymeric binder. The conductive additive and/or polymeric binder as included in the positive electrode24may be the same as or different from the conductive additive and/or polymeric binder as included in the negative electrode22.

In various aspects, the present disclosure provides methods for preparing positive electrodes, like the positive electrode24illustrated inFIG.1. For example, in certain variations, the positive electrode24may be prepared using a roll-to-roll hot calendaring method.

In various aspects, the present disclosure provides methods for preparing solid-state electrolyte layers, like the solid-state electrolyte layer26illustrated inFIG.1. For example, in certain variations, the solid-state electrolyte layer26may be prepared using a hot press process that includes a roll-to-roll hot calendared method.

In certain variations, the positive electrode24and/or the solid-state electrolyte layer26may be prepared using methods like those detailed in U.S. Pat. No. 10,680,281 (Filed Date: Apr. 6, 2017; Issue Date: Jun. 9, 2020; Title “Sulfide and Oxy-Sulfide Glass and Glass-Ceramic Films for Batteries Incorporating Metallic Anodes”; Inventors: Thomas A. Yersak, James R. Salvador, Han Nguyen), herein incorporated by reference in its entirety.

In various aspects, the present disclosure provides methods for preparing an all-solid-state battery, like the battery20illustrated inFIG.1. For example, in certain variations, the positive electrode24and solid-state electrolyte layer26may be prepared together using a hot press process. The combination may be subsequently stacked with a negative electrode22(e.g., lithium metal foil) to form the battery20.

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

Example materials may be prepared in accordance with various aspects of the present disclosure. For example, an example solid-state electrolyte layer210may include Li3YCl6and about 3 wt. % of Kevlar® fibers. The example solid-state electrolyte layer210may be prepared using a hot press process, such as detailed above. In certain variations, the hot press process may include applying a temperature greater than or equal to about 200° C. to less than or equal to about 250° C., and a pressure greater than or equal to about 75 MPa to less than or equal to about 450 MPa, for a period greater than or equal to about 0.1 minute to less than or equal to about 10 minutes. By way of comparison only, a comparative solid-state electrolyte layer220also including Li3YCl6and about 3 wt. % of Kevlar® fibers may be prepared using a cold press process, where temperatures are greater than or equal to about 10° C. to less than or equal to about 40° C.

FIG.2Ais a scanning microscopy image of the example solid-state electrolyte layer210, andFIG.2Bis a scanning microscopy image of the comparative solid-state electrolyte layer220. The following table compares the properties of the example solids-state electrolyte layer prepared using a hot press process and the comparative solid-state electrolyte layer prepared using a cold-press process.

AbsoluteBulkIonicDensityDensityPorosityConductivity(g/cm3)(g/cm3)(vol. %)(mS/cm)Cold Pressed Li3YCl62.51851.8426.90.133Hot Pressed Li3YCl62.51852.1913.10.123
As illustrated, the hot-pressed Li3YCl6has reduced porosity, as well as improved bulk density. The slight reduction in the ionic conductivity for the hot pressed solid-state electrolyte layer210is not problematic because the reduction is within error of measurement.

Example materials may be prepared in accordance with various aspects of the present disclosure. For example, an example positive electrode310may include about 70 wt. % of NCM622, about 2 wt. % of carbon black, and about 30 wt. % of Li3YCl6. The example positive electrode310may be prepared using a hot press process, such as detailed above. In certain variations, the hot press process may include applying a temperature greater than or equal to about 200° C. to less than or equal to about 250° C., and a pressure greater than or equal to about 75 MPa to less than or equal to about 450 MPa, for a period greater than or equal to about 0.1 minute to less than or equal to about 10 minutes. By way of comparison only, a comparative positive electrode320also including about 70 wt. % of NCM622, about 2 wt. % of carbon black, and about 30 wt. % of Li3YCl6may be prepared using a cold press process, where temperatures are greater than or equal to about 20° C. to less than or equal to about 40° C.

FIG.3Ais a scanning microscopy image of the example positive electrode310, andFIG.2Bis a scanning microscopy image of the comparative positive electrode320. The following table compares the properties of the example solids-state electrolyte layer prepared using a hot press process and the comparative solid-state electrolyte layer prepared using a cold-press process.

AbsoluteDensityBulk DensityPorosity(g/cm3)(g/cm3)(vol. %)Cold Pressed Cathode3.94843.3116.2Hot Pressed Cathode3.94843.4911.7
As illustrated, the example positive electrode310including Li3YCl6and prepared using the hot press process has reduced porosity, as well as improved bulk density.

Example batteries and battery cells may be prepared in accordance with various aspects of the present disclosure. For example, an example battery cell410may include a composite cathode that comprises about 70 wt. % of NCM622, about 2 wt. % of carbon black, and about 30 wt. % of Li3YCl6. The example battery cell410may also include an indium foil anode and a solid-state electrolyte layer that separates the composite cathode and the indium foil anode. The solid-state electrolyte may include Li3YCl6and about 3 wt. % of Kevlar® fibers. Like the composite cathode, the solid-state electrolyte may be prepared using a hot press process, such as detailed above. In certain variations, the hot press processes may include applying a temperature of about 200° C., and a pressure greater than or equal to about 75 MPa to less than or equal to about 450 MPa, for a period greater than or equal to about 1 minute to less than or equal to about 10 minutes. By way of comparison only, a comparison battery cell420may also include a composite cathode that comprises about 70 wt. % of NCM622, about 2 wt. % of carbon black, and about 30 wt. % of Li3YCl6. The comparison battery cell420may also include an indium foil anode and a solid-state electrolyte layer that separates the composite cathode and the indium foil anode. In this instance, however, the composite cathode and the solid-state electrolyte may be prepared using a cold press process, where temperatures are greater than or equal to about 10° C. to less than or equal to about 40° C.

FIG.4Ais a graphical illustration for the voltage versus specific capacity of the first charge and discharge curves comparing the example battery cell410to the comparison battery cell420, where the x-axis400represents specific capacity (mAh/g) of the cathode active materials, and the y-axis402represents voltage (V). As illustrated, the specific capacity of the hot pressed cell410is similar to that of the cold pressed cell420, which indicates that the catholyte is adequately stable versus the cathode active material during the hot pressing.

FIG.4Bis a graphical illustration comparing the normalized capacity versus number of cycles at different C-rates of the example battery cell410as compared to the comparison battery cell420, where the x-axis450represents cycle number, and the y-axis452represents the cell capacity normalized to the capacity of the first C/10discharge cycle after a rate test. As illustrate, the hot pressed cell410maintains a similar normalized capacity throughout the overall battery cycle life.