The Application of Permanent Magnets for High Capacitance Polyaniline-Modified Electrodes

Abstract

Supercapacitors are energy storage devices useful for their rapid charging and discharging but held back by poor energy density. Electrode conductivity and surface area are often increased to improve the energy storage of supercapacitors. Polyaniline (PANI) is an electroactive polymer used in supercapacitors for its high conductivity and ease of electrochemical deposition. It has also been shown that the application of a constant magnetic field can alter both the morphology of electrodeposited polymers and the rates of radical-based reactions. Additionally, the application of a strong magnetic field over a net movement of ions, such as is induced by an electric field or concentration gradient, induces rotational convection via the Lorentz force. In this work, we used a permanent magnet as a zero-energy-input method to influence the deposition of PANI for high capacitance electrodes with improved energy storage. The polymer was deposited onto glassy carbon or platinum electrodes using cyclic voltametric, potentiostatic, and pulsed potential techniques, and the capacitance of the fabricated electrodes was measured by cyclic voltammetry. With an optimized method, the application of a magnetic field increased the electrodes’ capacitance by more than 50% over the control. This presents a method for the fabrication of higher energy density supercapacitors with no additional energy input.