Sliceable, Moldable, and Highly Conductive Electrolytes for All-Solid-State Batteries

All-solid-state batteries (ASSBs) require solid electrolytes with high ionic conductivity, stability, and deformability for optimal energy and power density. We developed lithium-deficient lithium yttrium bromide (LYB) solid electrolytes, Li3-xYBr6-x (0 <= x <= 0.50), using a comelting method with controlled lithium deficiency. These electrolytes exhibit favorable mechanical properties such as high moldability and sliceability. The Li2.65YBr5.65 composition has an ionic conductivity of 4.49 mS cm(-1) at 25 degrees C and an activation energy of 0.28 eV. Compared to Li3YBr6, Li2.65YBr5.65 demonstrates improved rate performance and cycling stability in ASSBs. High-resolution X-ray diffraction confirms the formation of the LYB phase with a C2/m space group. Structural analysis reveals increased cation disorder and larger polyhedral volumes for x > 0 in Li3-xYBr6-x , contributing to reduced Li+ migration energy barriers. Bond valence site energy calculations and molecular dynamics simulations reveal enhanced 3D lithium-ion transport. NMR spectroscopy further highlights increased Li+ dynamics and impurity elimination.. Authors: Poudel, Tej P; Truong, Erica ; Oyekunle, Ifeoluwa ; Deck, Michael; Ogbolu, Bright O. DOE Contract: AC02-06CH11357