Polymeric Sulfur as a Li Ion Conductor.

Sun, Yufei; Zhong, Guiming; Zhao, Zheng; Cao, Min; Zhou, Han; Zhang, Sijing; Qian, Hao; Lin, Zhiyong et al. · Nano Lett · 2020

basic_science · Level V

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Abstract

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)<sub><i>n</i></sub>- backbone with a high sulfur content (up to 90 wt % S) was reported for the first time. The flexible -(S-S)<sub><i>n</i></sub>- chains with high S atom density create an intense "solvating" environment for Li<sup>+</sup> conduction, achieving an excellent Li<sup>+</sup> conductivity of 1.69 × 10<sup>-3</sup> S cm<sup>-1</sup> 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.