Composite electrode containing a sulfide-based solid electrolyte and an all-solid-state battery using the same

Low-porosity composite electrode using a mixture of sulfide glass-ceramics and argyrodite crystals with different Young's moduli

This technology improves all-solid-state battery performance by incorporating a mixture of sulfide-based glass-ceramics and sulfide-based crystals with different Young's moduli into the cathode or anode composite electrode, thereby reducing inter-particle voids and maximizing the contact area between active materials and the solid electrolyte.

All-solid-state batteries have historically faced high contact resistance due to voids within the electrode and at its interfaces. Furthermore, the repeated expansion and contraction of active materials during charge and discharge cycles lead to inter-particle cracking and reduced contact area, which degrades electrochemical performance.

This technology utilizes a solid electrolyte composed of a 25:75 weight ratio of soft sulfide-based glass-ceramics (14–20 E/GPa Young's modulus) and argyrodite-type sulfide-based crystals (22–30 E/GPa Young's modulus) within the composite electrode. The pliable glass-ceramics fill the gaps between crystalline particles, reducing internal porosity and maintaining interfacial contact during cycling. Suitable for thick-film cathodes and automotive modules operating under low stack pressure, this approach reduces reliance on high-pressure cell clamping equipment.

‍

‍

Key Features:

• A solid electrolyte layer positioned between the cathode and anode layers, containing only an argyrodite-type sulfide-based compound as the solid electrolyte
• A cathode layer and an anode layer disposed on opposite sides of the solid electrolyte layer
• A composite electrode containing a mixture of sulfide-based glass-ceramics and the same argyrodite-type sulfide-based crystals found in the solid electrolyte layer
• A solid electrolyte for composite electrodes consisting of glass-ceramics with a Young's modulus of 14–20 E/GPa and crystals with a Young's modulus of 22–30 E/GPa

‍

This invention was developed with support from the Defense Acquisition Program Administration's project for core technology development of high-safety, extreme-environment all-solid-state batteries.

‍