Enriched pseudocapacitive lithium storage in electrochemically activated carbonaceous vanadium(iv, v) oxide hydrate. Issue 26 (24th June 2020)

• Record Type: Journal Article
• Authors: Fernando, Joseph F. S.; Siriwardena, Dumindu P.; Firestein, Konstantin L.; Zhang, Chao; von Treifeldt, Joel E.; Lewis, Courtney-Elyce M.; Wang, Tony; Dubal, Deepak P.; Golberg, Dmitri V.
• Is Part Of: Journal of materials chemistry. Volume 8:Issue 26(2020)
• Page Start: 13183
• Page End: 13196
• Publication Date: 2020-06-24
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d0ta04191b
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Vanadium(iii ) oxide (V2 O3 ) derived, carbon integrated hydrated vanadium oxide (V5 O12 ·0.4H2 O) as an extrinsic pseudocapacitive material for excellent lithium storage in lithium ion battery anodes. Abstract : Hydrated vanadium oxides (HVOs) are promising (extrinsic) pseudocapacitive materials that extend the possibility to optimize electrochemical performance through fine-tuning their nanoscale porosity, structural disorder and conventional composition. These materials demonstrate the features of batteries ( i.e. high energy density) and supercapacitors (fast power output). However, most pseudocapacitive oxides are characterized by poor conductivity, which leads to high electrode resistance. Herein, an amorphous-like carbon-integrated vanadium oxide hydrate (V5 O12 ·0.4H2 O, CHVO) is engineered using a straightforward solvothermal approach, with improved conductivity, rich pore architecture and readily available nanoscale redox-active sites. The CHVO material shows superior performance as an anode in Li-ion batteries with a specific capacity of 1175 mA h g −1 at 50 mA g −1 in the 150 th cycle, which was maintained to 525 mA h g −1 over 600 cycles at 1000 mA g −1 . The half-cell can be charged to 403 mA h g −1 (1451 C g −1 ) at 4000 mA g −1 in ∼6 min. The cyclic voltammetry analysis shows that CHVO undergoes an electrochemical activation by forming a stable lithium vanadium oxide in the initial cycles. The research on electrochemical de(lithiation) mechanism of HVOs at low potentials (<1 V) is largely unexplored. In this context, real time measurements using in situ Transmission Electron Microscopy are provided to underpin the Li-ion transport process in CHVO electrodes. It is revealed that the carbon framework and peculiar structure of CHVO effectively buffer large volume expansions upon (de)lithiation. In addition, ex situ X-ray photoelectron spectroscopy and X-ray Diffraction measurements were collectively utilized to uncover a conversion-type reaction mechanism.