Enhancing Adsorption and Reaction Kinetics of Polysulfides Using CoP-Coated N-Doped Mesoporous Carbon for High-Energy-Density Lithium–Sulfur Batteries
Qi Cheng, Zhouhong Yin, Siyi Pan, Guizhi Zhang, Zhenxiao Pan, Xiaoyuan Yu, Yueping Fang, Huashang Rao, Xinhua Zhong
Abstract
Lithium–sulfur (Li–S) batteries have shown great potential in the next-generation energy storage devices due to high theoretical energy density and low cost. To obtain high-performance Li–S batteries, it is important to inhibit the polysulfide shuttle effect and improve the reaction kinetics of polysulfides. Herein, CoP nanoparticles coated by metal–organic framework-derived N-doped mesoporous carbon (CoP@N-C) composites are synthesized and applied in both a cathode for a sulfur host and a modified layer on a separator for high-energy-density Li–S batteries since the CoP component has strong chemical anchoring capability toward soluble polysulfides and high electrochemical activity toward polysulfides transformation. Meanwhile, the porous structure of conductive N-doped mesoporous carbon can not only buffer the volume variation of sulfur during the charge/discharge process but also enhance the charge transport rate in the cathode. The constructed batteries have demonstrated a high specific capacity of 1222 mAh g–1 (8.6 mAh cm–2) with a high sulfur areal loading of ∼7.0 mg cm–2 on cathodes, and a mass loading of 0.35 mg cm–2 for modified layer on separators. Its average capacity decay is only 0.076% per cycle after 100 cycles. This work presents the highly competitive performance of Li–S batteries on the areal capacity and capacity decay.