Stable all-solid-state Li-Te battery with Li_(3)TbBr_(6) superionic conductor

Rare-earth(RE)halide solid electrolytes(HSEs)have been an emerging research area due to their good electrochemical and mechanical properties for all-solid-state lithium batteries(ASSBs).However,only very limited types of HSEs have been reported with high performance.In this work,tens of grams of RE-HSE Li_(3)TbBr_(6)(LTbB)was synthesized by a vacuum evaporationassisted method.The as-prepared LTbB displays a high ionic conductivity of 1.7 mS·cm^(-1),a wide electrochemical window,and good formability.Accordingly,the assembled solid lithium-tellurium(Li-Te)battery based on the LTbB HSE exhibits excellent cycling stability up to 600 cycles,which is superior to most previous reports.The processes and the chemicals during the discharge/charge of Li-Te batteries have been studied by various in situ and ex situ characterizations.Theoretical calculations have demonstrated the dominant conductivity contributions of the direct[octahedral]-[octahedral]([Oct]-[Oct])pathway for Li ion migrations in the electrolyte.The Tb sites guarantee efficient electron transfer while the Li 2s orbitals are not affected during migration,leading to a low activation barrier.Therefore,this successful fabrication and application of LTbB have offered a highly competitive solution for solid electrolytes in ASSBs,indicating the great potential of RE-based HSEs in energy devices.