Polymeric Sulfur as a Li Ion Conductor

The typical polymer electrolyte matrix has been limited to the chains consisting of −C–C– or −C–O–C– or −Si–O– backbone with different solvating groups for decades. In this work, the polymeric sulfur consisting of −(S–S)n– backbone with a high sulfur content (up to 90 wt % S) was reported for the first time. The flexible −(S–S)n– chains with high S atom density create an intense “solvating” environment for Li+ conduction, achieving an excellent Li+ conductivity of 1.69 × 10–3 S cm–1 at 80 °C. Benefiting from its unique thermoplasticity, a hot-rolling process was also developed for fabricating the poly-S membrane. The symmetric solid-state Li cell using the membrane showed a high cycling stability over 300 h. The work offers a novel platform for chemists to design new polymer electrolytes that are quite different with conventional carbon-based polymer electrolytes.