Kinetic Enhancement of Sulfur Cathodes by N‐Doped Porous Graphitic Carbon with Bound VN Nanocrystals

Abstract The reaction kinetics of sulfur cathodes generally control the performance of lithium−sulfur (Li−S) batteries. Here, N‐doped porous graphitic carbon with bound VN nanocrystals (3D VN@N‐PGC), which is synthesized in one pot by heating a mixture of glucose as C source, urea as N source, and NH 4 VO 3 as V source, is reported to be an superior electrocatalytic cathode host for Li−S batteries. Notably, the VN nanocrystals, strongly bound to the N‐PGC network, form via in situ reactions among the thermolytic products of starting materials. The dopant N atoms and bound VN nanocrystals exhibit synergistic electrocatalytic effects to promote the cathode reactions of the Li−S cells. The observed enhancements are supported by density functional theory simulations and by the observation of electrocatalytic N‐ and V‐intermediate species, via X‐ray absorption near‐edge structure spectroscopy. Li−S cells assembled using 3D VN@N‐PGC as cathode host exhibit superior performance in terms of specific capacity (1442 mA h g −1 at 0.1 C), rate capability (641 mA h g −1 at 4 C), and cycle life (466 mA h g −1 after 1700 cycles at 2 C, corresponding to a capacity decay of 0.020% per cycle). The one‐pot methodology is facile and scalable and offers a new approach for synthesis of various metal nitride‐containing materials for other electrocatalytic applications.