A Polysulfide-Immobilizing Polymer Retards the Shuttling of Polysulfide Intermediates in Lithium-Sulfur Batteries.

Abstract

Lithium-sulfur batteries are regarded as one of the most promising candidates for next-generation rechargeable batteries. However, the practical application of lithium-sulfur (Li-S) batteries is seriously impeded by the notorious shuttling of soluble polysulfide intermediates, inducing a low utilization of active materials, severe self-discharge, and thus a poor cycling life, which is particularly severe in high-sulfur-loading cathodes. Herein, a polysulfide-immobilizing polymer is reported to address the shuttling issues. A natural polymer of Gum Arabic (GA) with precise oxygen-containing functional groups that can induce a strong binding interaction toward lithium polysulfides is deposited onto a conductive support of a carbon nanofiber (CNF) film as a polysulfide shielding interlayer. The as-obtained CNF-GA composite interlayer can achieve an outstanding performance of a high specific capacity of 880 mA h g^-1 and a maintained specific capacity of 827 mA h g^-1 after 250 cycles under a sulfur loading of 1.1 mg cm^-2 . More importantly, high reversible areal capacities of 4.77 and 10.8 mA h cm^-2 can be obtained at high sulfur loadings of 6 and even 12 mg cm^-2 , respectively. The results offer a facile and promising approach to develop viable lithium-sulfur batteries with high sulfur loading and high reversible capacities.