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

作者：Xinyue Yang, Shang Chen, Wenbin Gong, Xiaodong Meng, Junpeng Ma, Jie Zhang, Lirong Zheng, Héctor D. Abruña, Jianxin Geng · 发表于：Small · 年份：2020 · DOI：10.1002/smll.202004950 · 被引用次数：121 · 研究领域：Advanced Battery Materials and Technologies、Advancements in Battery Materials、Advanced battery technologies research

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.