Solid Power Operating, Inc.

An argyrodite companion compound having high ionic conductivity and low material hardness, a solid electrolyte composite including the argyrodite companion compound, and a solid state battery device including the argyrodite companion compound and/or the composite. The argyrodite companion compound is a sulfide solid electrolyte compound with a distinctive crystal structure defined by an XRD pattern featuring peaks at 2θ=20.9°±0.5°, 31°±0.5°, and 33°±0.5°. The argyrodite companion compound comprises at least lithium (Li), phosphorus (P), and sulfur (S).

Cathode active materials coated with a boron-containing additive are useful for suppressing thermal events when used in an electrochemical cell. Electrochemical cells may include a cathode layer that includes a boron additive, or may include a layer that contains the boron additive.

Methods for purifying metal sulfides include combining an alkali metal sulfide and composites that include a metal sulfide in an aprotic solvent, filtering undissolved solids from the mixture, and adding a secondary sulfide to the solution to precipitate the highly pure metal sulfide. The purified metal sulfides may be used in the production of solid-state electrochemical cells.

Processes for producing sulfide-based solid electrolytes include preparing a slurry by mixing a solvent with an alkali metal sulfide having a surface area greater than 6 m 2 /g or an alkaline earth metal sulfide having a surface area greater than 6 m 2 /g and a secondary sulfide. The slurry is then dried to produce the sulfide-based solid electrolyte.

Methods for producing metal sulfides generally include combining an alkali metal sulfide and a metal halide in an aprotic solvent to produce a mixture that includes an alkali metal halide and a metal sulfide. Additional methods include combining a first alkali metal sulfide, a second alkali metal sulfide, and a metal halide in an aprotic solvent to produce a mixture that includes a first alkali metal halide, a second alkali metal halide, and a metal sulfide. The methods may include adding a second solvent to cause an alkali metal halide to precipitate out of the mixture and improve the purity of the metal sulfide.

A method for determining enthalpy includes placing a reactive sample within a sealable vessel, sealing the sealable vessel, placing the sealable vessel within a vacuum chamber, causing a vacuum to be formed within the vacuum chamber, causing the sample to react after causing the vacuum to be formed, measuring a temperature parameter during the reaction of the sample, and determine an enthalpy via the measured temperature parameter.

An encapsulated electrode for an electrochemical cell and a method for producing an encapsulated electrode. The encapsulated electrode structure has a first solid-state electrolyte composite (SSE) that has a top surface, a bottom surface, and a peripheral surface. Another layer of the encapsulated electrode structure is the electrode that has a top surface, a bottom surface, and a peripheral surface. Yet another layer of the encapsulated electrode structure is a second SSE that has a top surface, a bottom surface, and a peripheral surface. The first SSE is arranged so as to be attached to the electrode, wherein the bottom surface of the first SSE is attached to the top surface of the electrode. The bottom surface of the electrode is attached to the top surface of the second SSE. Pressure is applied to this stack so that the SSEs deform and encapsulate the electrode.

A solid electrolyte material comprises Li, T, X and A wherein T is at least one of P, As, Si, Ge, Al, and B; X is one or more halogens or N; A is one or more of S and Se. The solid electrolyte material has peaks at 17.8°±0.75° and 19.2°±0.75° in X-ray diffraction measurement with Cu-Kα(1,2)=1.5418 Å and may include glass ceramic and/or mixed crystalline phases.

A method comprises positioning a sample within an interior volume of a sealable vessel, positioning a first electrode adjacent to the sample such that a first gap is formed between the sample and the first electrode, positioning a second electrode within the interior volume, sealing the sealable vessel, and positioning the sealable vessel within a bomb calorimeter. The method further includes causing an energy to flow between the first electrode and second electrode to cause a reaction in the sample, measuring at least one temperature change within the bomb calorimeter induced by the reaction in the sample, and determining a change in enthalpy via the measured at least one temperature change.

Coated cathode active materials include a cathode active material that is coated by a hydroxide-containing material, such as a metal hydroxide. The coated cathode active materials may be incorporated into electrochemical cells, including solid-state batteries. Electrochemical cells including the coated cathode active materials have improved capacity retention as compared to electrochemical cells including un-coated cathode active materials.