Electrochemical in situ construction of vanadium oxide heterostructures with boosted pseudocapacitive charge storage. Issue 3 (19th December 2019)

• Record Type: Journal Article
• Authors: Dong, Ran; Song, Yu; Yang, Duo; Shi, Hua-Yu; Qin, Zengming; Zhang, Mingyue; Guo, Di; Sun, Xiaoqi; Liu, Xiao-Xia
• Is Part Of: Journal of materials chemistry. Volume 8:Issue 3(2020)
• Page Start: 1176
• Page End: 1183
• Publication Date: 2019-12-19
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c9ta12097a
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : An in situ electrochemical deposition method is demonstrated as an efficient strategy to build high-quality vanadium oxide heterostructures with enhanced electrochemical performance. Abstract : Pseudocapacitive materials hold extraordinary promise for improving the energy densities of electrochemical capacitors but are often limited to electrodes with ultralow mass loadings ( e.g. <1 mg cm −2 ) due to the sluggish mass transport kinetics in thicker electrodes. Here a V5 O12 /VO2 heterojunction nanomaterial with a built-in electric field near the heterointerface is fabricated on a 3D graphite substrate via an in situ electrochemical method for the first time, which can remarkably enhance the capacitive performance by improving the electron/ion delivery kinetics. The V5 O12 /VO2 electrode (mass loading ∼10.8 mg cm −2 ) achieves a high areal capacitance of 5.03 F cm −2 (465 F g −1 ) with a good rate capability and long cycle life, outperforming the V5 O12 and VO2 counterparts, as well as the state-of-the-art reported VO X electrodes. An asymmetric supercapacitor assembled using V5 O12 /VO2 as the negative electrode and MnO2 as the positive electrode can deliver high areal/volumetric energy densities of 1.42 mW h cm −2 /11.85 mW h cm −3 . An extrapolated gravimetric energy density of 18.6 W h kg −1 can also be achieved, based on the entire weight of the device (76.6 mg cm −2, active material ratio ∼30%), representing a critical step of pushing pseudocapacitors toward practical applications.