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

Abstract

This work reports on a finding of mT magnetic field induced energy storage enhancement of MnO 2 -based supercapacitance electrodes (magneto-supercapacitor).Electrodes with MnO 2 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 1.34 mT, MnO 2 /ECNFs shows a magneto-enhanced capacitance of 141.7 F g -1 vs. 119.2 F g -1 (~19% increase) with absence of magnetic field at the voltage sweeping rates of 5 mV s -1 . The mechanism of the magneto-supercapacitance is discussed and found that the magnetic susceptibility of the MnO 2 significantly improves the electron transfer reaction of pseudoreaction 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 MnO 2 /ECNFs electrode without sacrificing its life cycle stability.

Magnetic Field‐Enhanced 4‐Electron Pathway for Well‐Aligned Co3O4/Electrospun Carbon Nanofibers in the Oxygen Reduction Reaction

“…[15][16][17][18] To ensure that the fuel cell generates the maximum powero utput,a4-electron pathway (from oxygen to water) is necessary because the 2-electron pathway (from oxygen to hydrogen peroxide) involved in the cathodic process seriously compromises the energy yield of the fuel cell. [23,24] Herein, we propose an ew strategy to combinet he stable synthesis of ap aramagnetic transition metal oxide electrocatalyst and its electron transfer rate enhancement to maximize a4 -electron pathway in the ORR. [19,20] With aview to ar oute to a4 -electron pathway by effectively decomposing generated hydrogen peroxide,c atalysis by hematite nanoparticles supported on carbon nanotubes [21] or GC [22] was reported.…”

“…In previous studies, it was found that an external magnetic field over am aterial with magnetic susceptibility could facilitate the electrochemical reactions, owing to the effects of Lorentz force acting on moving charge/ions, charge density gradientm odulation, electron state excitation, and/or oscillatory magnetization. [23,24] Herein, we propose an ew strategy to combinet he stable synthesis of ap aramagnetic transition metal oxide electrocatalyst and its electron transfer rate enhancement to maximize a4 -electron pathway in the ORR.…”

Facile Synthesis and Electrochemical Properties of Perovskite‐type CeMnO3 Nanofibers

“…However, poor electron conductivity limits its application into supercapacitors due to the low specific capacitance . As a typical semiconductor, manganese oxide has gained specific attention in electronic devices and supercapacitors thanks to its high bandgap, low cost, abundance, low toxicity, high theoretical capacitance (1370 F g −1 ), variable valence states, and stable chemical properties . As a typical rare earth based‐perovskite, the electrochemical behaviors of LaMnO 3 have been widely investigated owing to its stable thermal and structural properties.…”

Stable Low‐Current Electrodeposition of α‐MnO2 on Superaligned Electrospun Carbon Nanofibers for High‐Performance Energy Storage

“…CNFs are well known for their inexpensive production, freestanding nature, large porosity, and high conductivity as electrode materials for supercapacitor applications. Electrospinning, which uses electric force to draw charged threads of polymer solutions or polymer melts into nanofibers, has become an efficient fiber production method for creating porous electrospun CNFs (ECNFs) with a subsequent carbonization . Aligned ECNF structures can be used as scaffolds to uniformly support metal oxide nanoarchitectures because their alignment can significantly enhance the deposition rate by shortening the distance of electron transport.…”