Open AccessHierarchical Nanosheets/Walls Structured Carbon‐Coated Porous Vanadium Nitride Anodes Enable Wide‐Voltage‐Window Aqueous Asymmetric Supercapacitors with High Energy Density
Author(s) -
Huang Jun,
Peng Zhongyou,
Xiao Yingbo,
Xu Yazhou,
Chen Lingfang,
Xiong Yushuai,
Tan Licheng,
Yuan Kai,
Chen Yiwang
Publication year - 2019
Publication title -
advanced science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.388
H-Index - 100
ISSN - 2198-3844
DOI - 10.1002/advs.201900550
Subject(s) - nanosheet , supercapacitor , materials science , anode , cathode , vanadium nitride , aqueous solution , capacitance , power density , chemical engineering , electrolyte , electrochemistry , vanadium , energy storage , electrode , carbon fibers , nanotechnology , nitride , optoelectronics , composite material , layer (electronics) , chemistry , metallurgy , power (physics) , physics , quantum mechanics , composite number , engineering
The energy density of aqueous asymmetric supercapacitors (ASCs) is usually limited by low potential windows and capacitances of both anode and cathode. Herein, a facile strategy to fabricate hierarchical carbon‐coated porous vanadium nitride nanosheet arrays on vertically aligned carbon walls (CC/CW/p‐VN@C) as anode for aqueous ASCs is reported. The potential window of CC/CW/p‐VN@C electrode can be stably extended to –1.3 to 0 V (vs Ag/AgCl) with greatly improved specific capacitance (604.8 F g −1 at 1 A g −1 ), excellent rate capability (368 F g −1 at 60 A g −1 ), and remarkable electrochemical stability. To construct ASCs, a Birnessite Na 0.5 MnO 2 nanosheet arrays (CC/CW/Na 0.5 MnO 2 ) cathode is similarly built. Benefiting from the matchable potential windows and high specific capacitances of the rationally designed anode and cathode, aqueous CC/CW/p‐VN@C||CC/CW/Na 0.5 MnO 2 ASCs with a wide voltage window of 2.6 V are fabricated. Moreover, the ASCs showcase an ultrahigh energy density up to 96.7 W h kg −1 at a high power density of 1294 W kg −1 , and excellent cycling stability (92.5% retention after 10 000 cycles), outperforming most of previously reported ASCs and even comparable to that of organic electrolyte supercapacitors (SCs). This efficient strategy for fabricating 2.6 V aqueous ASCs suggests a promising research system for high energy density SCs.