Molecular Simulations Guided Polymer Electrolyte towards Superior Low-Temperature Solid Lithium-Metal Batteries

Low-temperature operation is a challenge for solid-lithium-metal batteries (LMBs), and insufficient ionic conductivity is the main obstacle. Herein, guided by the molecular dynamics simulations (MDS), a solid polymer electrolyte (SPE) based on poly(1,3-dioxolane) (PDOL) with sufficient ionic conductivity at low temperature is reported. In situ X-ray diffraction (XRD) and differential scanning calorimetry (DSC) tests reveal that the PDOL-based SPE could well maintain amorphous nature at low temperatures, contributing to excellent ionic transport. The MDS analysis of the Li-O coordination environment indicates that more oxygen atoms bonded with Li+ in PDOL than in poly(ethylene oxide) (PEO) at low temperatures, thus we could envision the preponderance of PDOL as a better polymer matrix of SPE for low-temperature solid LMBs. It delivers a high capacity of 103 mAh g-1 and 85% retention for 200 cycles for Li||LiFePO4 at -20 °C, showing great potential for application in low-temperature solid LMBs in cold climates.