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Kinetic Enhancement of Sulfur Cathodes by N‐Doped Porous Graphitic Carbon with Bound VN Nanocrystals
Author(s) -
Yang Xinyue,
Chen Shang,
Gong Wenbin,
Meng Xiaodong,
Ma Junpeng,
Zhang Jie,
Zheng Lirong,
Abruña Héctor D.,
Geng Jianxin
Publication year - 2020
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.202004950
Subject(s) - cathode , nanocrystal , graphitic carbon nitride , materials science , dopant , sulfur , chemical engineering , nanoparticle , carbon fibers , nanotechnology , doping , catalysis , chemistry , composite number , photocatalysis , organic chemistry , optoelectronics , engineering , metallurgy , composite material
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.