Synergistic pincer catalysis by closely adjacent single atoms and nanoclusters for superior lithium-sulfur batteries

The practical application of lithium-sulfur (Li-S) batteries is seriously impeded by the notorious shuttle effect and sluggish reaction kinetics. Herein, we develop an advanced sulfur electrocatalyst that integrates single-atom Co-N₄ moieties with Co nanoclusters on N-rich hollow carbon nanospheres (Co-ACSA@NC). The proximity of single atoms and nanoclusters establishes a synergistic “pincer” interaction with polysulfides through dual modes of coordinate and chemical bonding. Moreover, electron donation from the Co nanocluster enhances the bonding between polysulfide and Co-N₄, further improving the immobilization and catalytic conversion of sulfur species. The hollow and porous carbon support not only exposes the abundant active sites efficiently, but also serves as a confined nanoreactor for well-tamed sulfur reactions. As a result, the S/Co-ACSA@NC cathode exhibits excellent cyclability over 500 cycles with minimal attenuation of 0.018% per cycle. A high areal capacity of 11.15 mAh cm⁻² can be obtained even under high sulfur loading (13.1 mg cm⁻²) and lean electrolyte (E/S = 4.0 μL mg⁻¹), while a 2.38-Ah pouch cell is also demonstrated with a commendable energy density over 307.7 Wh kg⁻¹. This work offers a unique “pincer” catalysis strategy for boosting sulfur electrochemistry, paving the way to high-performance and practically viable Li-S batteries.