High-areal-capacity and long-cycle-life all-solid-state battery enabled by freeze drying technology

Abstract

The all-solid-state battery (ASSB) has been widely recognized as the critical next-generation energy storage technology due to its high energy density and safety. However, stable cycling at high cathode loadings is difficult to be realized due to the poor interfacial contacts and ion transportation caused by large particle size of halide solid electrolytes (SEs). Herein, freeze-drying technology is first exploited to synthesize Li₃InCl₆ SE with 80% of its particle size smaller than 200 nm, which greatly improves the charge transmission capability of the composite cathode and the overall interfacial contacts of an ASSB. The corresponding ASSBs employ sulfide SEs as the anolyte for their high ionic conductivity and small-particle halide SEs as the catholyte for their high oxidation stability to combine the advantages of both SE chemistries for excellent electrochemical performance, including an ultra-long life of 30 000 cycles with >70% capacity retention at a superior current rate/density (20C/9.98 mA cm⁻²). Even at beyond-normal cathode loadings (9.8 mA h cm⁻²) and cathode active material (CAM) proportion (80%), the ASSB can still deliver a specific capacity of 107 mA h g⁻¹ with a capacity retention rate close to 90% after 100 cycles. Unprecedented CAM proportion (95%) and current rate (49C) are also realized. These encouraging results pave the way for future practical application of high-energy-density ASSBs with high cathode loadings and fast-charging capabilities.