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

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Low-temperature operation of solid lithium-metal batteries (LMBs) is hindered by insufficient ionic conductivity in solid polymer electrolytes (SPEs).
• Developing stable and conductive SPEs is crucial for enabling LMBs in cold environments.

Purpose of the Study:

• To develop a novel SPE with high ionic conductivity at low temperatures for solid LMBs.
• To investigate the structural and ionic transport properties of poly(1,3-dioxolane) (PDOL)-based SPEs.

Main Methods:

• Molecular dynamics simulations (MDS) to analyze Li-O coordination and ionic transport.
• In situ X-ray diffraction (XRD) and differential scanning calorimetry (DSC) to study the structural stability at low temperatures.
• Electrochemical performance testing of Li||LiFePO4 cells at -20 °C.

Main Results:

• PDOL-based SPE maintains an amorphous structure at low temperatures, facilitating ionic transport.
• MDS reveals superior Li+ coordination in PDOL compared to PEO at low temperatures.
• The SPE achieved a high capacity of 103 mAh g-1 with 85% retention over 200 cycles at -20 °C.

Conclusions:

• PDOL is a promising polymer matrix for developing high-performance SPEs for low-temperature solid LMBs.
• The enhanced ionic conductivity and structural stability of PDOL-based SPEs are critical for cold-climate battery applications.
• This work paves the way for reliable solid LMBs in demanding environmental conditions.