▎ 摘　　要

Sluggish reaction kinetics of lithium-sulfur (Li-S) battery is the key issue affecting cycle capacity and rate performance. Highly conductive and catalytically active sulfur host is still a research hotspot in recent years. Herein, the sulfur host of Co nanoparticles anchored on the Co-N-x active centers grafted nitrogen-doped graphene (Co/Co-N-x@NG) with high catalytic activity and electrical conductivity was prepared via a simple and feasible in situ method. The cobalt-based nanocatalytic center exhibits efficient sulfur conversion efficiency. Moreover, the Co-N-x coordination group is beneficial to inhibit the agglomeration of cobalt nanoparticles to form large particles and further improve the catalytic activity. In addition, the graphene structure formed at low temperature based on the two-dimensional guide of dicyandiamide in combination with the catalytic graphitization of cobalt nanoparticles has excellent electrical conductivity. Owing to the high catalytic activity, appropriate adsorption ability, and excellent electrical conductivity, the Co/Co-N-x@NG applied as sulfur cathode matrix exhibits high capacities of 1300.3 mA h g(-1) at 0.1 C and 884.2 mA h g(-1) at 2 C, and good cycling stability with a capacity decay of only 0.069% per cycle at 2 C for 705 cycles. (C) 2021 Elsevier B.V. All rights reserved.