Theoretical insights into interfacial stability and ionic transport of Li(2)OHBr solid electrolyte for all-solid-state batteries

Li-rich antiperovskite materials are promising candidates as inorganic solid electrolytes (ISEs) for all-solid-state Li-ion batteries (ASSLIBs). However, the material faces several pressing issues for its application, concerning the phase stability and electrochemical stability of the synthesized material and the Li-ion transport mechanism in it. Herein, we performed first-principles computational studies on the phase stability, interfacial stability, defect chemistry, and electronic/ionic transport properties of Li(2)OHBr material. The calculation results show that the Li(2)OHBr is thermodynamically metastable at 0 K and can be synthesized experimentally. This material exhibits a wider intrinsic electrochemical stability window (0.80–3.15 V) compared with sulfide solid electrolytes. Moreover, the Li(2)OHBr displays significant chemical stability when in contact with typical cathode materials (LiCoO(2), LiMn(2)O(4), LiFePO(4)) and moisture. The dominant defects of Li(2)OHBr are predicted to be V(Li(−)) and Li(i)(+), corresponding to lower Li-ion migration barriers of 0.38 and 0.49 eV, respectively, while the replacement of some of the OH(−) by F(−) is shown to be effective in decreasing migration barriers in Li(2)OHBr. These findings provide a theoretical framework for further designing high performance ISEs.