Boron-Doped Dinickel Phosphide to Enhance Polysulfide Conversion and Suppress Shuttling in Lithium–Sulfur Batteries
Jiatong Li, Guangyue Li, Rui Wang, Qiya He, Wan Liu, Chaoquan Hu, Huigang Zhang, Junfeng Hui, Fengwei Huo
Abstract
Lithium–sulfur (Li–S) batteries are promising for next-generation high-energy energy storage systems. However, the slow reaction kinetics render mobile polysulfides hardly controlled, yielding shuttling effects and eventually damaging Li metal anodes. To improve the cyclability of Li–S batteries, high-efficiency catalysts are desired to accelerate polysulfide conversion and suppress the shuttling effect. Herein, we studied a doping system with Ni 2 P and Ni 2 B as the end members and found a B-doped Ni 2 P catalyst that demonstrates high activity for Li–S batteries. As anionic dopants, B demonstrates an interesting reverse electron transfer to P and tunes the electronic structure of Ni 2 P dramatically. The resultant B-doped Ni 2 P exhibits short Ni–B bonds and strong Ni–S interaction, and the electron donation of B to P further enhances the adsorption of polysulfide on catalysts. The S–S bonds of polysulfides were activated appropriately, therefore decreasing a low energy barrier for conversion reactions.