Low-Temperature-Resilient Polymer Electrolytes for High-Performance Quasi-Solid Lithium Batteries
Solid-state lithium batteries (SSLBs) are promising next-generation energy storage systems due to their high safety and energy density. However, poor low-temperature performance of solid-state electrolytes remains a critical challenge. Here, we present a facile and scalable approach for synthesizing a low-temperature-resilient polymer electrolyte based on ethylene-vinyl acetate (EVA), leveraging its unique molecular structure for enhanced lithium-ion transport. The EVA polymer electrolyte (EPE) demonstrates a high ionic conductivity of 5.13×10−4 S cm−1 at room temperature and retains a remarkable conductivity of 2.72×10−5 S cm−1 at −40 °C. This superior performance is attributed to the synergistic interaction between the ester functional groups of EVA and lithium salts, which reduces the ion dissociation energy barrier and facilitates efficient ion migration. The EPE enables stable lithium plating/stripping cycling for over 3000 h at −40 °C and supports long-term cycling of LiFePO4-based full cells at −40 °C for over 900 cycles. This work highlights the potential of cost-effective, scalable EPEs for next-generation SSLBs, particularly in extreme environmental conditions.