Effects of Li1.3al0.3ti1.7(Po4)3 Solid-State Electrolytes on the Safety of Hybrid Solid-Liquid Batteries

Hybrid solid-liquid batteries (HSLBs) are emerging as promising solutions to address the safety issues of lithium-ion batteries. However, the effects of solid-state electrolytes (SEs) on battery safety remain unclear, hindering the large-scale application of HSLBs. This paper presents a comprehensive investigation on the safety performance of HSLBs with different amount of nano-sized Li1.3Al0.3Ti1.7(PO4)3 (LATP) SEs in the LiNi0.9Co0.05Mn0.05O2 cathode under thermal, electrical and mechanical abuse conditions. The HSLBs with LATP SEs exhibit significantly enhanced tolerance to overcharge, as the battery with 5 wt.% LATP does not go into thermal runaway throughout the whole overcharge process. In-depth characterizations reveal that the LATP SEs experience electrochemical delithiation during overcharge and introduce a protective coating layer on the cathode surface, thus effectively mitigating the cathode structural changes and cathode-electrolyte interfacial reactions. Benefiting from the coating layer, the HSLBs with LATP SEs also exhibit reduced temperature rise rate and retarded thermal runaway during the accelerating rate calorimetry and oven tests, as well as enhanced rate performance and cycling stability. Finally, the safety, electrochemical performance and cost of HSLBs and conventional LIBs are comprehensively compared through a radar graph, aiming to provide guidance for the rational design of high-energy-density and high-safety batteries.