Phase and Orbital Engineering Effectuating Efficient Adsorption and Catalysis toward High‐Energy Lithium−Sulfur Batteries

Abstract The delicate construction of electrocatalysts with high catalytic activity is a strategic method to enhance the kinetics of lithium–sulfur batteries (LSBs). Adjusting the local structure of the catalyst is always crucial for understanding the structure–activity relationship between atomic structure and catalyst performance. Here, in situ induction of electron‐deficient B enables phase engineering Mo 2 C, realizing the transition from hexagonal ( h ‐Mo 2 C) to cubic phase ( c ‐B‐Mo 2 C). Meanwhile, the empty sp 3 orbital of B favors the effective bonding with electron‐rich sulfur, creates a more valid orbital engineering available. Relying on the binary engineering via B doping, the adsorption and conversion of polysulfides are promoted. Hence, the c ‐B‐Mo 2 C based cell achieves a low‐capacity degradation of 0.04% with the coulombic efficiency exceeding 99.8% in 1000 cycles. Uniform Li + transport is consistently achieved at 2 mA cm −2 for over 600 h. A 6.67Ah‐ c ‐B‐Mo 2 C based pouch cell has a high energy density of up to 502.1 Wh kg −1 (E/S ratio of 2.4 µL mg S −1 ), while the pouch cell of 2 Ah exhibits an energy density of 372 Wh kg −1 more than 100 cycles. This study takes advantage of the combined engineering method to provide a guiding approach for elevating the activity of the electrocatalysts rationally.