Efficient Activation of Li 2 S by Transition Metal Phosphides Nanoparticles for Highly Stable Lithium–Sulfur Batteries

作者：Huadong Yuan, Xianlang Chen, Guangmin Zhou, Wenkui Zhang, Jianmin Luo, Hui Huang, Yongping Gan, Chu Liang, Yang Xia, Jun Zhang, Jianguo Wang, Xinyong Tao · 发表于：ACS Energy Letters · 年份：2017 · DOI：10.1021/acsenergylett.7b00465 · 被引用次数：300 · 研究领域：Advanced Battery Materials and Technologies、Advancements in Battery Materials、Advanced battery technologies research

Considerable research efforts have been devoted to the lithium–sulfur battery due to its advantages such as high theoretical capacity, high energy density, and low cost. However, the shuttle effect and the irreversible deposition of Li 2 S result in severe capacity decay and low Coulombic efficiency. Herein, we discovered that the transition metal phosphides cannot only trap the soluble polysulfides but also effectively catalyze the decomposition of Li 2 S to improve the utilization of active materials. Compared with the cathodes without transition metal phosphides, the cathodes based on Ni 2 P, Co 2 P, and Fe 2 P all exhibit higher reversible capacity and improved cycling performance. The Ni 2 P-added electrode delivers capacities of 1165, 1024, 912, 870, and 812 mAh g –1 at 0.1, 0.2, 0.5, 1.0, and 2.0 C, respectively, and high capacity retention of 96% after 300 cycles at 0.2 C. Even with a high sulfur mass loading of 3.4 mg cm –2, the capacity retention remains 90.3% after 400 cycles at 0.5 C. Both density functional theory calculations and electrochemical tests reveal that the transition metal phosphides show higher adsorption energies and lower dissociation energies of Li 2 S than those of carbon materials.