Self‐Supported Tungsten Nitride and Carbide Heterostructures with Vanadium Doping Tandemly Catalyze the Conversion of Polysulfides for Lithium‐Sulfur Batteries
Yongqing Chen, Xudong Zhang, Qidi Chen, Daoping Cai, Chaoqi Zhang, Baisheng Sa, Hongbing Zhan
Abstract
Abstract The intrinsically sluggish sulfur reduction reaction kinetics and serious shuttle effect of soluble lithium polysulfides (LiPSs) severely impede the practical commercialization of lithium‐sulfur (Li‐S) batteries. Herein, self‐supported tungsten nitride and carbide heterostructures with vanadium doping that are directly grown on carbon cloth substrate (CC@V‐W 2 N/WC 1‐ x ) are creatively designed for Li‐S batteries, which can tandemly catalyze the liquid–liquid conversion and liquid–solid conversion of polysulfide intermediate free of any interference from polymer binders and conductive additives. Noteworthy, the rich heterointerfaces and vanadium doping are beneficial for rapid charge transfer, strong chemical adsorption toward LiPSs, massive exposed catalytically active sites, and remarkable catalytic activities. Consequently, Li‐S batteries assembled with the CC@V‐W 2 N/WC 1‐ x /S cathodes exhibit high sulfur utilization, superior rate capability, and decent long‐term cycling stability. Furthermore, experimental analyses and theoretical calculations jointly substantiate that the V‐W 2 N component is more effective in catalyzing the conversion of long‐chain LiPSs, while the V‐WC 1‐ x benefits the favorable Li 2 S deposition kinetics. More importantly, the Li‐S pouch cells are also fabricated to demonstrate their feasibility for practical applications. This work not only highlights the significance of tandem catalysis on the consecutive conversion of LiPSs but also provides a feasible avenue for developing highly efficient electrocatalysts toward high‐performance Li‐S batteries.