Effective improvement of electrochemical performance of electrodeposited MnO2 and MnO2/reduced graphene oxide supercapacitor materials by alcohol pretreatment

Abstract

Abstract In this work, basing on the traditional electrodeposition method, we improve the structure and electrochemical performance of MnO2 and MnO2/reduced graphene oxide (MnO2/RGO) electrode materials by alcohol infiltrated substrate process that introduces ethanol oxidation reaction on nickel foam substrate surface. After alcohol treatment, the deposited MnO2 on substrate obtains more uniform thickness and looser distribution, RGO obtains larger deposition area with compact distribution. In addition, the capacity, rate, specific energy, specific power and cycle performance have been greatly improved. MnO2 electrode shows the specific capacitance increasing from 153 and 103 F g − 1 to 270 and 190 F g − 1 at the current densities of 1 and 5 A g − 1, respectively. MnO2/RGO electrode shows specific capacitance increasing from 343 to 254 F g − 1 to 467 and 307 F g − 1 at 1 and 5 A g − 1, respectively. Moreover, the specific capacitance of MnO2 and MnO2/RGO electrodes keep 83.9% and 93.1% retention after 2500 cycles at the large current density of 5 A g − 1, respectively. Based on some scientific universals, we look forward to the proposed alcohol infiltrated substrate process for this work, which may be favorable for the performance enhancement of a series of MnO2-based supercapacitor materials, not only for MnO2 and MnO2/RGO.