Unveiling the Synergy of Single-Atom Cobalt Catalysts with Hollow Carbon Spheres for Enhanced Lithium-Sulfur Battery Performance

Lithium-sulfur (Li-S) batteries boast a theoretical energy density as high as 2600 Wh kg-1, positioning them as a highly attractive option for future advanced energy storage systems. For all that, challenges such as slow transformation kinetics and shuttle effects associated with lithium polysulfide (LiPSs) have seriously hindered its practical application. In this study, we present a new method for the synthesis of carbon hollow sphere-supported cobalt monatomic catalyst (Co-N-C). This is realized through the pyrolytic-coordination method, utilizing a precursor rich in imide (-RC=N-) polymers. This synthesis method not only improves the adsorbability and catalytic activity of LiPS, but also significantly weakens the shuttle effect, but also generates Co-N-C with superior conductivity, abundant hollow structures, and a high specific surface area, thus efficiently capturing and restricting the movement of LiPSs intermediates. The dispersed Co monoatomic catalysts (Co SACs) are anchored to a highly conductive nitrogen-doped carbon framework and exhibit a symmetric N-coordination active site (CO-N4), to ensure fast redox kinetics of LiPS and Li2S2/Li2S solid state products. The lithium-sulphur battery with Co-N-C as the sulphur carrier showed an amazing discharging capacity of 1146.6 mAh g-1 at the discharge rate of 0.1C, and maintained excellent performance at a high current density of 2 C, and the capacity decay rate in 500 cycles was only 0.086% per cycle, reflecting excellent long-term cycle stability. This study highlights the key role of the synergistic effect between single atom cobalt catalysts and hollow carbon spheres in enhancing the efficiency of lithium-sulfur (Li-S) batteries. It also provides valuable insights into the construction and fabrication of highly active monatomic catalysts.Display Omitted The catalytic conversion efficiency of lithium polysulphides is significantly enhanced when embedded in hollow carbon architectures, which serves as a critical strategy for optimising the electrochemical behavior of next-generation Li-S batteries.