title: Niobium Nitride Nb4N5as a New High-Performance Electrode Material for Supercapacitors.
abstract: Supercapacitors suffer either from low capacitance for carbon or derivate electrodes or from poor electrical conductivity and electrochemical stability for metal oxide or conducting polymer electrodes. Transition metal nitrides possess fair electrical conductivity but superior chemical stability, which may be desirable candidates for supercapacitors. Herein, niobium nitride, Nb4N5, is explored to be an excellent capacitive material for the first time. An areal capacitance of 225.8 mF cm-2, with a reasonable rate capability (60.8% retention from 0.5 to 10 mA cm-2) and cycling stability (70.9% retention after 2000 cycles), is achieved in Nb4N5nanochannels electrode with prominent electrical conductivity and electrochemical activity. Faradaic pseudocapacitance is confirmed by the mechanistic studies, deriving from the proton incorporation/chemisorption reaction owing to the copious +5 valence Nb ions in Nb4N5. Moreover, this Nb4N5nanochannels electrode with an ultrathin carbon coating exhibits nearly 100% capacitance retention after 2000 CV cycles, which is an excellent cycling stability for metal nitride materials. Thus, the Nb4N5nanochannels are qualified for a candidate for supercapacitors and other energy storage applications.
authors.affiliation: CAS Key Laboratory of Materials for Energy Conversion and State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China.
authors.forename: Houlei
authors.initials: H
authors.lastname: Cui
authors.affiliation: CAS Key Laboratory of Materials for Energy Conversion and State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China.
authors.forename: Guilian
authors.initials: G
authors.lastname: Zhu
authors.affiliation: Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular Engineering Peking University Beijing 100871 China.
authors.forename: Xiangye
authors.initials: X
authors.lastname: Liu
authors.affiliation: CAS Key Laboratory of Materials for Energy Conversion and State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China.
authors.forename: Fengxin
authors.initials: F
authors.lastname: Liu
authors.affiliation: CAS Key Laboratory of Materials for Energy Conversion and State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China.
authors.forename: Yian
authors.initials: Y
authors.lastname: Xie
authors.affiliation: CAS Key Laboratory of Materials for Energy Conversion and State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China.
authors.forename: Chongyin
authors.initials: C
authors.lastname: Yang
authors.affiliation: CAS Key Laboratory of Materials for Energy Conversion and State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China.
authors.forename: Tianquan
authors.initials: T
authors.lastname: Lin
authors.affiliation: CAS Key Laboratory of Materials for Energy Conversion and State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China.
authors.forename: Hui
authors.initials: H
authors.lastname: Gu
authors.affiliation: CAS Key Laboratory of Materials for Energy Conversion and State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China; Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular Engineering Peking University Beijing 100871 China.
authors.forename: Fuqiang
authors.initials: F
authors.lastname: Huang
keywords: Nb4N5 nanochannels; areal capacitance; cycling stability; pseudocapacitance; supercapacitors