Fast-charging batteries based on dual-halogen solid-state electrolytes†

Developing fast-charging technology is inevitable for the widespread adoption of electric vehicles. Therefore, high-performance all-solid-state batteries (ASSBs) assembled with stable electrodes and solid-state electrolytes (SSEs) with superior ionic conductivity are in demand. Herein, we develop dual-halogen SSEs Li₃YCl_6−xI_x that increase the ionic conductivity of trigonal Li₃YCl₆ (LYC) by more than one order of magnitude. Structural distortions and perturbative local structures of Li⁺ and Y³⁺ were studied, which confirmed the successful introduction of I⁻ ions. Li₄Ti₅O₁₂ (LTO) was chosen as the cathode material for ASSBs, and the batteries showed great stability after 1000 cycles at a high charge–discharge rate of 4.0C, with the initial capacity retained at 80%, suggesting promising applications as fast-charging ASSBs.