Dramatically comprehensive improved electrochemical performances of symmetric and asymmetric supercapacitors under external magnetic field

Abstract

Recently, magnetic field (MF) has been described as a potential way to improve the properties of electrode materials, which significantly enhances the ion diffusion behavior and material wettability. We first synthezised for the first time a comparable carbon-based electrode material (GCA) including active carbon, reduced graphene and carbon nanotubes through a facile stirring method for further research under MF. Herein, 0.15 T of MF induced by two NdFeB magnets was applied on the supercapacitor devices to enhance the energy density, which increased by about 62% for the symmetric supercapacitor (SSC: from 11.2 to 18.1 W h kg⁻¹). An asymmetric supercapacitor composed of the prepared GCA as the anode and NiCoFe/NiCoFe–OH as the cathode was also assembled for research. And it was found that the whole electrochemical performance significantly improved (for example, energy density increased by about 22% for the asymmetric supercapacitor, i.e., from 50.6 to 61.4 W h kg⁻¹).