Phase and Orbital Engineering Effectuating Efficient Adsorption and Catalysis toward High-Energy Lithium-Sulfur Batteries.

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 MoC, realizing the transition from hexagonal (h-MoC) to cubic phase (c-B-MoC). Meanwhile, the empty sp 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-MoC 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 for over 600 h. A 6.67Ah-c-B-MoC based pouch cell has a high energy density of up to 502.1 Wh kg (E/S ratio of 2.4 µL mg ), while the pouch cell of 2 Ah exhibits an energy density of 372 Wh kg 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.