Reasonable design a high-entropy garnet-type solid electrolyte for all-solid-state lithium batteries

Abstract

Traditional garnet solid electrolyte (Li7La3Zr2O12) suffers from low room temperature ionic conductivity, poor air stability, high sintering temperature and energy consumption. Considering the development prospects of high-entropy materials with high structural disorder and strong component controllability in the field of electrochemical energy storage, herein, a novel high-entropy garnet-type oxide solid electrolyte, Li5.75Ga0.25La3Zr0.5Ti0.5Sn0.5Nb0.5O12 (LGLZTSNO) was constructed by partially replacing the Li and Zr sites in Li7La3Zr2O12 with Ga and Ti/Sn/Nb elements, respectively. The experimental and density functional theory (DFT) calculation results show that the high-entropy LGLZTSNO electrolyte has preferable room temperature ion conductivity, air stability, interface contact performance with lithium anode, and the ability to suppress lithium dendrites. Thanks to the improvement of electrolyte performance, the critical current density of Li/Ag@LGLZTSNO/Li symmetric cell was increased from 0.42 to 1.57 mA cm−2, and the interface area specific impedance (IASR) was reduced from 765.2 to 42.3 Ω cm2. Meanwhile, the Li/Ag@LGLZTSNO/LFP full cell also exhibits excellent rate performance and cycling performance (148 mA h g−1 at 0.1 C and 124 mA h g−1 at 0.5 C, capacity retention up to 84.8% after 100 cycles at 0.1 C), showing the application prospects of high-entropy LGLZTSNO solid electrolyte in high-performance all solid state lithium batteries.