Space-confined synthesis of CoSe2-NC nanoclusters anchored on honeycomb-like carbon framework towards high-performance lithium sulfur battery

Lithium–sulfur (Li-S) battery has been considered to be one of the next-generation high-energy-density rechargeable battery systems due to the high theoretical energy density, low cost, and environmental friendliness. However, the commercial application of Li-S battery still faces problems such as sluggish redox kinetics and infamous shuttle effect of sulfur cathode, which result in low sulfur utilization, poor cycle life, and unsatisfied rate performance. Herein, we proposed a CoSe2-NC nanocluster anchored honeycomb-like carbon framework (CoSe2-NC@HCF) as sulfur host aiming to accelerate sulfur conversion and inhibit polysulfide shuttle in Li-S electrochemistry via space-confined growth and in situ selenization. The obtained CoSe2-NC@HCF provides strong chemical adsorption capability and massive polar cobalt active sites as well as abundant and continuous hierarchical pores supplying adequate sulfur storage space and physical confinement. The S/CoSe2-NC@HCF cathode with sulfur content of 83.24 wt% delivers high sulfur utilization with initial discharge capacity of 1212.9 mAhg−1 at 0.1 C, excellent rate performance with 1094.7 mAh·g–1 at 1C rate, and good cyclability with low-capacity decay rate of 0.12% up to 600 cycles.