Improved supercapacitor performance of MnO2-electrospun carbon nanofibers electrodes by mT magnetic field

JOURNAL OF POWER SOURCES

卷:358

Article

Zeng, Zheng¹  Liu, Yiyang¹  Zhang, Wendi¹  Chevva, Harish¹  Wei, Jianjun¹ 

[1] Univ North Carolina Greensboro, Dept Nanosci, JSNN, Greensboro, NC 27401 USA

关键词: Manganese dioxide;    Pseudocapacitor;    Carbon nanofibers;    Magnetic field;    Energy storage enhancement;   

DOI  :  10.1016/j.jpowsour.2017.05.008

来源: Elsevier

【 摘 要 】

This work reports on a finding of mT magnetic field induced energy storage enhancement of MnO2-based supercapacitance electrodes (magneto-supercapacitor). Electrodes with MnO2 electrochemically deposited at electrospun carbon nanofibers (ECNFs) film are studied by cyclic voltammetry (CV), galvanostatic charge/discharge, electrochemical impedance spectroscopy (EIS), and life cycle stability tests in the presence/absence of milli-Tesla (mT) magnetic fields derived by Helmholtz coils. In the presence of a 1.34 mT magnetic field, MnO2/ECNFs shows a magneto-enhanced capacitance of 141.7 F g(-1), vs. 119.2 Fg(-1)(-19% increase) with absence of magnetic field at a voltage sweeping rate of 5 mV s(-1). The mechanism of the magneto-supercapacitance is discussed and found that the magnetic susceptibility of the MnO2 significantly improves the electron transfer of a pseudo-redox reaction of Mn(IV)/Mn(III) at the electrode, along with the magnetic field induced impedance effect, which may greatly enhance the interface charge density, facilitate electrolyte transportation, and improve the efficiency of cation intercalation/de-intercalation of the pseudocapacitor under mT-magnetic field exposure, resulting in enhancement of energy storage capacitance and longer charge/discharge time of the MnO2/ECNFs electrode without sacrificing its life cycle stability. (C) 2017 Elsevier B.V. All rights reserved.

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