Pseudocapacitive Behavior of Ce Modified CoO through a Galvanostatic Charge–Discharge Test: Distinguishing between Surface-Control and Diffusion-Control Current

Abstract

This paper presents an attempt on deconvoluting diffusion-control current (i d ) and surface-control current (i s ) from total current in a galvanostatic charge−discharge (GCD) test. Using this strategy, the pseudocapacitive behavior of nanosized Ce-CoO dispersed on graphene support was studied in detail. The results show that i d is greatly affected by operating potential and occupies some proportion of the total pseudocapacitive current. The main functions of Ce in the composite material include promoting the proportion of i s or inhibiting i d and finally stimulating a specific capacitance (C s ) value increased from 192 to 726 F g −1 . The Bode curve in the low-frequency region also proves that Ce can promote the performance of pseudocapacitance.