An alternating voltage induced method has been developed for the fabrication of porous Co₃O₄ sheets. The electrochemical investigation of Co₃O₄ sheets in LiOH, NaOH and KOH electrolytes reveals that the size of the hydrated ionic radius can have impact on its ionic conductivity, resulting in the best rate behaviour in the KOH electrolyte. Based on the results above, Co₃O₄ sheets were further utilized in a 2 M KOH aqueous electrolyte and exhibit a maximum specific capacitance of 288 F g⁻¹ at a current density of 1 A g⁻¹.