Engineering the Undercoordinated Edge‐Rich Single‐Crystal Microreactors for High‐Performance Lithium─Sulfur Batteries

Abstract Lithium─sulfur (Li─S) batteries have garnered extensive research interest due to their high theoretical capacity and cost‐effectiveness. However, their practical application is hindered by severe shuttle effects and sluggish conversion kinetics. Here, the development of a novel microreactor composed of undercoordinated edge‐rich single‐crystal nickel─cobalt bimetallic oxides embedded within a conductive carbon nanotube network (NCO/CNT), as an electrocatalyst for Li─S batteries is reported. The single‐crystal bimetallic oxide matrix ensures high structural stability during reactions, while its abundant edge sites provide abundant active catalytic centers. Structural analyses reveal pronounced oxygen undercoordination within NCO/CNT, with these unsaturated sites demonstrating strong adsorption and catalytic activity, effectively promoting sulfur species immobilization and conversion. Complementary theoretical calculations indicate that the unique edge‐rich undercoordinated design optimizes the electronic configuration of metal atoms, enhancing electron exchange with sulfur species. Benefiting from these features, Li─S batteries incorporating NCO/CNT achieve an initial discharge capacity of 1327.1 mAh g ⁻¹ at 0.2C, and a high areal capacity of 5.4 mAh cm ⁻² under a sulfur loading of 5.83 mg cm ⁻² , with 96.3% capacity retention after 50 cycles. This work offers insights into the design of high‐performance sulfur microreactors, paving the way for efficient and sustainable sulfur electrochemistry.