A dual-matrix hybridization strategy for synthesis of cationic-anionic double-doped Li_2.99Y_0.99Zr_0.01Br_1.6Cl_4.4 halide solid electrolyte

Abstract

The advancement of all-solid-state lithium-ion batteries (ASSLBs) is constrained by the poor ionic conductivity of the solid electrolyte. In addition to sulfides and oxides, new halide electrolytes with the general formula Li₃MX₆ (M = In, Y, Sc, Er, etc.; X = Cl, Br, etc.) are expected to be used in ASSLBs. Halide solid-state electrolytes (SSEs) have received intensive research interests owing to their high oxidation stability, superior ductility, and well compatibility with the cathode for utilization in ASSLBs. Nevertheless, most of the reported halide SSEs exhibit unsatisfactory ionic conductivity mainly due to the absence of effective diffusion channels for fast Li-ion transport. In this work, we propose a dual-matrix hybridization strategy for cationic/anionic co-doping of the SSE lattice, employing high-energy ball milling method to synthesize the novel Li_2.99Y_0.99Zr_0.01Br_1.6Cl_4.4 for the first time. Compared with the original Li₃YCl₆, the ionic conductivity of Li_2.99Y_0.99Zr_0.01Br_1.6Cl_4.4 has increased by nearly 5 times. This new synthetic strategy will shed light on the further development of solid-state electrolyte modification.