Modeling and simulating a microelectromechanical system microsupercapacitor

Abstract

A mathematical model for double-layer and faradaic processes in microsupercapacitor using finite element analysis is presented here. Different from previous work, the mathematical model here can be applied to an asymmetric geometrical model, other than traditional layer-to-layer structure. COMSOL Multiphysics 4.2 software is used to solve the system of partial differential equations, in order to simulate the electrochemical reactions in the electrodes of the microsupercapacitor dynamically. A microsupercapacitor was designed and fabricated according to the geometrical model, and charge/discharge curves were obtained by the galvanostatic charge/discharge test. The potential curves show good agreement with the simulation results and display the typical behavior of a steady voltage rise and subsequently a steady voltage drop during a cycle of charge and discharge. Besides, the H+ ion concentration profile development during charge and discharge can also be obtained through the simulation. Thus, the mode in this work can play a significant role in studying the detailed electrochemical process and predicting the performance of the supercapacitor.