Low-Temperature-Resilient Polymer Electrolytes for High-Performance Quasi-Solid Lithium Batteries

• • EPE achieves an ionic conductivity of 5.13×10−4 S cm−1 at room temperature and retains 2.72×10−5 S cm−1 at −40 °C, demonstrating a 53-fold decrease but still sufficient for low-temperature operation, enabling practical SSLBs in subzero environments. • • Stable lithium plating/stripping cycling for over 3000 h at −40 °C indicates exceptional interfacial stability and dendrite suppression, critical for long-cycle-life lithium metal batteries in cold climates. • • LiFePO4-based full cells maintain stable cycling for over 900 cycles at −40 °C, proving the electrolyte's compatibility with commercial cathodes and its potential for real-world cold-weather energy storage. • • The use of ethylene-vinyl acetate copolymer offers a cost-effective, scalable synthesis route compared to complex polymer architectures, addressing economic barriers for large-scale production of low-temperature solid electrolytes.