Vacuum evaporation-assisted reaction: sustainable solution for application of rare earth-based halide solid-state electrolytes

All-solid-state lithium-ion batteries (ASLIBs) are important and promising electric energy storage devices with high stabilities and energy densities. As burgeoning key materials in ASLIBs, rare earth (RE) halide solid-state electrolytes (SEs) have better overall electrochemical performance than do oxide and sulfide SEs. Technologies for the efficient preparation, mass production and recycling of RE halide SEs (HSEs) are challenges that urgently need to be overcome. In this study, products and byproducts can be separated in an orderly manner via a vacuum evaporation-assisted reactor for the green synthesis of 15 kinds of RE HSEs and nine kinds of RE halide perovskites. The as-prepared HSEs have high ionic conductivity (mS cm-1 level) and wide electrochemical windows (1.4 – 4.2 V). The assembled Li–S ASLIBs were stable for up to 550 cycles. This work realized massive preparation and recycling of RE HSEs and crucial metal resources.