Catalytic Mo2C decorated hollow mesoporous carbon spheres as sulfur host for lithium-sulfur batteries with high sulfur loading

Abstract

Hybrid structures as sulfur host materials have been proven to be an effective way to improve the electrochemical property of lithium-sulfur (Li–S) batteries. However, how to construct hybrid nanomaterials with reasonable structure and composition remains a challenge. Herein, the Mo2C nanoparticles grown on the surface of hollow mesoporous carbon spheres (HMCS@Mo2C) are synthesized as an effective sulfur host for Li–S batteries with high sulfur loading. In this hybrid structure, the HMCS can guarantee high sulfur loading, high-speed electron/ion transport, and sufficient buffer for volume change, and the Mo2C nanoparticles as effective catalysts significantly accelerate the conversion of polysulfides. Consequently, the as-prepared HMCS@Mo2C–S cathode demonstrates superb cyclic stability with a capacity decay rate of 0.065% for 500 cycles at 1 ​C. Impressively, HMCS@Mo2C–S cathode with high areal sulfur loading of 5.4 ​mg ​cm−2 can deliver a high specific capacity of 451.2 mAh g−1 after 500 cycles at 0.5 ​C. In addition, the preparation of HMCS@Mo2C is simple, feasible, and low cost. It is hoped that this work will provide new insight into the rational design of sulfur host materials integrating reasonable structure with an effective catalyst for Li–S batteries with high sulfur loading.