APPLICATIONS OF TECHNOLOGY:
- Power distribution (e.g., energy storage)
- Electric vehicles
- Personal electronics
- Provides structural stability
- Improves energy density
- Reduces interfacial impedance
- Obviates the need for co-sintering
- Cycles with stability at room temperature
All-solid-state batteries (ASSBs) potentially offer higher energy density, longer cycle life, and better inherent safety than state-of-the-art lithium ion batteries (LIBs). However, successful fabrication of ASSBs with ceramic electrolytes has primarily been restricted to small-scale thin film devices due to processing difficulties and interfacial challenges. To address these issues, researchers at the Berkeley Lab have used tape-casting and freeze tape casting (FTC) methods to construct bi-/tri-layer frameworks with structurally resilient porous layers. FTC is a scalable method for creating thin porous films, with good control over total pore volume, pore size, and morphology.
Researchers utilized ceramic processing methods to create the backbone architecture, which typically comprises porous/dense bilayer or porous/dense/porous trilayer ceramic electrolyte frameworks. Then, they infiltrated the active electrode material and other components into the porous layers. A soft solid electrolyte with a relatively low melting point was subsequently introduced to fill in the pores and establish good contact among the components. A feature of the FTC prepared scaffolds is the low tortuosity (approaching unity) pores, which aids infiltration and shortens lithium diffusion path lengths. Additionally, the composition can be modified to be compatible with the characteristics of the active material used. Despite the use of a cathode that was 4-6 times thicker than usual, the ASSBs exhibited superior electrochemical performance. When the solid-state-cells were cycled at room temperature between 2.5-4.4 V at 0.1 C rate, they demonstrated discharge capacities of 125-135 mAh g-1.
To the best of the researchers’ knowledge, this is the first report of successful room temperature cycling of a bulk type ASSB using the present compositions. The fabrication methods overcome the limitations of previous technologies by obviating the need for co-sintering via the soft solid electrolyte that connects the active material with the ceramic electrolyte. Ultimately, this architectural design permits stable operation of the ASSBs and can be applied to solid-state batteries of diverse cell chemistries. With solid-state batteries being regarded as next generation energy storage devices, the novel technology can be used to power mobile electronic devices and electric vehicles, and may hold applications in grid energy storage as well.
DEVELOPMENT STAGE: Proven principle
FOR MORE INFORMATION:
Eongyu Yi, Hao Shen, Stephen Heywood, Judith Alvarado, Dilworth Y. Parkinson, Guoying Chen, Stephen W. Sofie, and Marca M. Doeff, “All-Solid-State Batteries Using Rationally Designed Garnet Electrolyte Frameworks,” ACS Applied Energy Materials. 2020. DOI: 10.1021/acsaem.9b02101
STATUS: Patent pending. Available for licensing or collaborative research.
SEE THESE OTHER BERKELEY LAB TECHNOLOGIES IN THIS FIELD:
Hybrid Solid Electrolytes for Safe, Reliable All-Solid-State Rechargeable Lithium Batteries 2015-048