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

This paper presents an attempt on deconvoluting diffusion-control current (id) and surface-control current (is) 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 id 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 is or inhibiting id and finally stimulating a specific capacitance (Cs) 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.