Single-atomic Co-B2N2 sites anchored on carbon nanotube arrays promote lithium polysulfide conversion in lithium-sulfur batteries

Due to low cost, high capacity, and high energy density, lithium-sulfur (Li-S) batteries have attracted much attention; however, their cycling performance was largely limited by the poor redox kinetics and low sulfur utilization. Herein, predicted by density functional theory calculations, single-atomic Co-B2N2 site-imbedded boron and nitrogen co-doped carbon nanotubes (SA-Co/BNC) were designed to accomplish high sulfur loading, fast kinetic, and long service period Li-S batteries. Experiments proved that Co-B2N2 atomic sites can effectively catalyze lithium polysulfide conversion. Therefore, the electrodes delivered a specific capacity of 1106 mAh g(-1) at 0.2 C after 100 cycles and exhibited an outstanding cycle performance over 1000 cycles at 1 C with a decay rate of 0.032% per cycle. Our study offers a new strategy to couple the combined effect of nanocarriers and single-atomic catalysts in novel coordination environments for high-performance Li-S batteries.