Lattice Strain and Charge Localization Dual Regulation of Phosphorus‐Doped CoSe₂/MXene Catalysts Enable Kinetics‐Enhanced and Dendrite‐Free Lithium‐Sulfur Batteries

Phase engineering is considered an effective strategy to regulate the electrocatalytic activity of catalysts for Li–S batteries (LSBs). However, the underlying origin of phase‐dependent catalytic ability remains to be determined, which significantly impedes the design principles of high‐performance catalytic materials for LSBs. Herein, heteroatom‐doped engineering can trigger phase transformation from mixed‐phased cubic and orthorhombic cobalt diselenide into pure orthorhombic structure with a tensile strain and enhanced charge localization. The upshift of the d ‐band center and enhanced Bader charge at Se sites synergistically strengthen the interaction with Li and S sites in polysulfide species, thus endowing the transformed P‐MoSe 2 /MXene with high catalytic activity and uniform lithium deposition for LSBs. Consequently, the P‐CoSe 2 /MXene Li–S batteries demonstrate a high‐rate capability of 603 mAh g −1 at 4C, and an excellent cyclability of 652 mAh g −1 at 1C over 500 cycles with a degradation rate of 0.076% per cycle. The work provides an in‐depth insight into the fundamental design principles of effective catalysts for LSBs.