Capacitance Measurements of MnO_X Films Deposited by Reactive Sputtering of a Mn Target

Abstract

Manganese oxide thin films are deposited on graphite foils by a dry process, one step reactive radio frequency (RF) magnetron sputtering with different volume flow rates of oxygen and sputtering time. Maximum mass specific capacitance of 320.26 F g⁻¹ is obtained in 0.5 M LiCl as well as with optimum sputtering conditions [volume flow rate of oxygen=10 sccm (cm³ min⁻¹) and sputtering time=60 min], and this demonstrates its good mass specific capacitance at a sweep rate of 100 mV s⁻¹. Furthermore, the mass specific capacitance and the geometric specific capacitance increase at lower volume flow rates of oxygen, but decrease at higher volume flow rates of oxygen. Moreover, the electrochemical stability of the electrode increases with increasing sputtering time.