High-rate sodium-ion storage of vanadium nitride via surface-redox pseudocapacitance  

作　　者：Qiulong Wei Tingyi Huang Xiaojuan Huang Binhao Wang Yalong Jiang Dafu Tang Dong-Liang Peng Bruce Dunn Liqiang Mai 

机构地区：[1]Department of Materials Science and Engineering,Fujian Key Laboratory of Surface and Interface Engineering for High Performance Materials,College of Materials,Xiamen University,Xiamen,China [2]State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,Wuhan University of Technology,Wuhan,China [3]Department of Materials Science and Engineering,University of California Los Angeles,Los Angeles,California,USA

出　　处：《Interdisciplinary Materials》2023年第3期434-442,共9页交叉学科材料（英文）

基　　金：National Natural Science Foundation of China,Grant/Award Numbers:22005256,22179113;Fundamental Research Funds for the Central Universities,Grant/Award Number:20720210045;Natural Science Foundation of Fujian Province of China,Grant/Award Number:2020J01034。

摘　　要：Vanadium nitride(VN)electrode displays high-rate,pseudocapacitive responses in aqueous electrolytes,however,it remains largely unclear in nonaqueous,Na+-based electrolytes.The traditional view supposes a conversion-type mechanism for Na+storage in VN anodes but does not explain the phenomena of their size-dependent specific capacities and underlying causes of pseudocapacitive charge storage behaviors.Herein,we insightfully reveal the VN anode exhibits a surface-redox pseudocapacitive mechanism in nonaqueous,Na+-based electrolytes,as demonstrated by kinetics analysis,experimental observations,and first-principles calculations.Through ex situ X-ray photoelectron spectroscopy and semiquantitative analyses,the Na+storage is characterized by redox reactions occurring with the V5+/V4+to V3+at the surface of VN particles,which is different from the well-known conversion reaction mechanism.The pseudocapacitive performance is enhanced through nanoarchitecture design via oxidized vanadium states at the surface.The optimized VN-10 nm anode delivers a sodium-ion storage capability of 106 mAh g−1 at the high specific current of 20 A g−1,and excellent cycling performance of 5000 cycles with negligible capacity losses.This work demonstrates the emerging opportunities of utilizing pseudocapacitive charge storage for realizing high-rate sodium-ion storage applications.

关 键 词：high-rate capability PSEUDOCAPACITANCE sodium-ion storage vanadium nitride 

分 类 号：TM53[电气工程—电器]