Electrochemical Capacitor Behavior of RuO₂ Nanosheets in Buffered Solution and Its Application to Hybrid Capacitor

Abstract

The electrochemical property of RuO₂ nanosheets in acetic acid-lithium acetate buffered electrolytes was studied in an attempt to understand the charge storage mechanism in neutral solutions and to improve the charge storage capability of aqueous hybrid capacitors. High specific capacitance and good rate capability were obtained for RuO₂ nanosheets in acetic acid buffered solution containing Li⁺ (pH ∼ 5.3). Maximum capacitance of 1038 F g⁻¹ was achieved, which is higher than the values in acidic electrolyte. Using RuO₂ nanosheet electrodes as positive electrode in acetic acid-lithium acetate buffered electrolyte with a multi-layered Li negative electrode, high specific energy of 724 Wh kg⁻¹ based on the positive electrode mass was attained.