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Oxygen Vacancy Modulation of Bimetallic Oxynitride Anodes toward Advanced Li‐Ion Capacitors
Author(s) -
Wang Shouzhi,
Li Lili,
He Weidong,
Shao Yongliang,
Li Yanlu,
Wu Yongzhong,
Hao Xiaopeng
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202000350
Subject(s) - materials science , anode , x ray photoelectron spectroscopy , electrochemistry , bimetallic strip , vacancy defect , nanowire , capacitor , oxide , optoelectronics , nanotechnology , electrode , chemical engineering , metal , nuclear magnetic resonance , chemistry , metallurgy , physics , voltage , quantum mechanics , engineering
Binary metal oxides (such as NiCo 2 O 4 ) are regarded as attractive electrode materials for advanced energy storage devices since they offer more electrochemical activity and higher capacity than monometal oxide. However, the volume expansion and low electronic conductivity are the main bottleneck seriously hindering their application. To overcome these barriers, a novel strategy that introduces a bimetallic oxynitride layer (NiCoON) with oxygen vacancy to the surface of NiCo 2 O 4 nanowires as an anode for Li‐ion capacitors (LICs) is proposed. The oxygen vacancy on the surface and the modulation of multiple valence states are investigated by the electron paramagnetic resonance, X‐ray photoelectron spectroscopy characterization, and first‐principles calculation. Benefiting from the merits of substantially improved electrical conductivity and increased concentration of active sites, the optimized NiCoON electrode delivers remarkable capacity (1855 mAh g −1 at 0.2 A g −1 ) and rate performance. The LIC device assembled by NiCoON anodes and N‐doped carbon nanowire cathodes delivers excellent rate capability, high energy density (148.5 Wh kg −1 ), and outstanding power density (30 kW kg −1 ). This study provides a new pathway for developing bimetallic oxides with an improved performance in electrochemical energy storage, conversion fields, and beyond.