Highly dispersed MoP encapsulated in P-doped porous carbon boosts polysulfide redox kinetics of lithium-sulfur batteries

Abstract

Lithium-sulfur batteries have been considered as a promising next-generation battery system because of their high theoretical energy density and natural abundance of sulfur. However, the loss of active material and the sluggish kinetics of polysulfide severely hinder the large-scale application. Herein, the highly dispersed MoP nanocrystallites encapsulated in phosphorus-doped porous carbon (MoP@PC) is successfully synthesized by metal organic framework–derived strategy. As a polysulfide reservoir, MoP@PC can efficiently capture and convert polysulfides by constructing a well-designed adsorption-conversion cooperative interface to enhance kinetics. Typically, the lithium-sulfur cell with a MoP@PC reservoir exhibits an initial specific capacity of 1158 mA h g-1 at 0.5 C and an enhanced sulfur utilization of 17% (285 mA h g-1). The present strategy provides applicable guidelines for synthesizing other highly dispersed transition metal compounds and optimizing the reaction interface of electrocatalyst material for lithium-sulfur battery.