Abstract In this study, a simple method involving immersion and heat treatment was used to modify graphite felt, enabling the attachment of Co 3 O 4 and altering its morphology. The etching process created nanorod structures, which significantly increased the surface area and improved wettability. A Co(NO 3 ) 2 concentration of 4 m m demonstrated optimal electrochemical activity compared to pristine graphite felt. Following the modification, the electrochemically active surface area reached a high value of 131.71 cm 2 , the charge transfer resistance decreased to 12.27 Ω, and the exchange current density increased to 25.02 mA/cm 2 . Cyclic voltammetry measurements revealed that GF4 exhibited reversible redox activity across various scan rates and maintained stability over 50 cycles at a scan rate of 1.0 mV/s, with I pa / I pc = 1.18 and ∆ E p = 220 mV. These findings indicate that the modification method improves the performance of graphite felt cathodes in vanadium redox flow batteries, emphasizing its potential for energy storage.
Vo et al. (Thu,) studied this question.