A Facile Humidity‐Induced Porous Framework Filled with In Situ Initiated Gel Electrolyte for Stabilizing Li1.3Al0.3Ti1.7(PO4)3/Li Interface

Abstract NASICON‐type Li1.3Al0.3Ti1.7(PO4)3 (LATP) is a highly competitive solid‐state electrolyte due to its high ionic conductivity, nice air stability, and low cost. However, the interface failure resultingfrom the continuous side reaction between LATP and lithium anode limits its further development. Here, a humidity‐induced porous polyvinylidene fluoride (PVDF) framework filled with in situ initiated poly(1,3‐dioxolane) (PDOL)‐based gel electrolyte is developed to stabilize LATP/Li interface. The porous PVDF framework isolates the direct contact between LATP and Li. The internally filled PDOL‐based gel electrolyte contributes to the smooth and uniform Li+ plating/stripping, which mitigates the interfacial side reaction induced by lithium dendrite penetration. In addition, the used ring‐opening polymerization initiator, Zn(OTf)2, is reduced on the lithium anode to form Li‐Zn alloy which further optimizes Li+ transport. Lithium symmetrical cells assembled with the modified LATP above can stably operate for over 1800 h at 0.1 mA cm−2. Also, LFP‐based solid‐state lithium batteries assembled with the modified LATP represent a favourable capacity retention of 94.8% for 700 cycles at 0.2C and 92% for 400 cycles at 0.5C. This work provides a facile organic interface strategy to realize stable LATP/Li interface and shows the promising potential to be universally applicable for stabilizing various rigid and unstable electrolyte/Li interface.