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.