High‐Energy Aqueous Asymmetric Supercapacitors via Synergistic Design of Electrodes Derived from Hierarchical Vanadium Dioxide Nanocomposites. Issue 2 (22nd January 2022)

• Record Type: Journal Article
• Authors: He, Qichang; Peng, Zhongyou; Li, Shulong; Tan, Licheng; Chen, Yiwang
• Is Part Of: ChemElectroChem. Volume 9:Issue 2(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-01-22
• Subjects: asymmetric supercapacitors -- vanadium dioxide -- nanocomposite -- potential window -- energy storage; Electrochemistry -- Periodicals; 541.37
• DOI: 10.1002/celc.202101576
• Languages: English
• ISSNs: 2196-0216

Abstract

Abstract: The energy density of aqueous asymmetric supercapacitors (ASCs) is confined by the narrow voltage and the mismatching between cathode and anode. Vanadium dioxide (VO2 ) can contemporaneously operate in both negative and positive potential windows for efficient aqueous ASCs. Nonetheless, their intrinsically inferior cycling stability and capacity seriously restrain the overall capacitive properties. Herein, a novel manganese dioxide (MnO2 ) coated VO2 (VO2 @MnO2 ) with hierarchical structure is firstly fabricated as cathode with enlarged potential (0 to 1.2 V) and superb specific capacitance (608.9 F g −1 at 1.0 A g −1 ). Subsequently, VO2 coated by a thin layer of carbon (VO2 @C) owning high electric conductivity and superb structure stability is designed to match with VO2 @MnO2 cathode. Eventually, the VO2 @C//VO2 @MnO2 aqueous ASCs exhibit stable voltage (2.2 V), maximal energy density (77.1 Wh kg −1 ) and favourable cycling stability. This research inspires the design and preparation of matchable electrode materials, providing a feasible method for the development of aqueous ASCs with broad voltage. Abstract : VO2 @MnO2 cathode and VO2 @C anode are firstly fabricated to enhance specific capacitance and structure stability of pure VO2 . Benefiting from the complementary voltage windows and uniquely hierarchical structure of cathode and anode, the as‐assembled VO2 @C//VO2 @MnO2 asymmetric supercapacitors (ASCs) operate a broad and stable working voltage of 2.2 V. Meanwhile, the ASCs display excellent specific capacitance, energy density and cycling stability.