Phosphorous-Containing Oxygen-Deficient Cobalt Molybdate as an Advanced Electrode Material for Supercapacitors

Liu, Shude, Yin, Ying, Ni, Dixing, Hui, Kwan San, Hui, Kwun Nam, Ouyang, Chu-Ying and Jun, Seong Chan (2019) Phosphorous-Containing Oxygen-Deficient Cobalt Molybdate as an Advanced Electrode Material for Supercapacitors. Energy Storage Materials, 19. pp. 186-196. ISSN 2405-8297

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Abstract

The intrinsically poor electrical conductivity and insufficient number of electrochemically active sites of transition-metal oxides hamper their wide application in high-performance supercapacitors. Herein, we demonstrate an effective strategy of creating phosphorus-containing cobalt molybdate (CoMoO4) with oxygen vacancies (P-CoMoO4-x) on nickel foam for use as a supercapacitor electrode. Experimental analyses and theoretical calculations reveal that the electronic structure of P-CoMoO4-x can be efficiently modulated by incorporating P heteroatoms and O vacancies, thereby simultaneously reducing the energy band gap and increasing electrical conductivity. Moreover, incorporating P into P-CoMoO4-x weakens the Co-O bond energy and induces the low oxidation states of molybdenum species, facilitating surface redox chemistry and improving electrochemical performance. Accordingly, the optimized P-CoMoO4-x electrode exhibits a high specific capacity of 1368 C g−1 at a current density of 2 A g−1, and it retains 95.3% of the initial capacity after 5000 cycles at a high current density of 10 A g−1. An asymmetric supercapacitor assembled with the optimized P-CoMoO4-x as positive electrode and activated carbon as negative electrode delivers a high energy density of 58 W h kg−1 at a power density of 850 W kg−1 as well as achieves excellent cycling lifespan.

Item Type: Article
Uncontrolled Keywords: comoo4,phosphorus incorporation,oxygen vacancy,electrochemical performance,supercapacitors
Faculty \ School: Faculty of Science > School of Mathematics
Related URLs:
Depositing User: LivePure Connector
Date Deposited: 30 Oct 2018 10:31
Last Modified: 19 May 2020 00:05
URI: https://ueaeprints.uea.ac.uk/id/eprint/68699
DOI: 10.1016/j.ensm.2018.10.022

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