Microwave-assisted synthesis of Cu_xTe_y as an anode material for supercapacitors

The low negative-electrode capacitance of supercapacitors results in low energy density, thereby severely limiting their practical applications. In this study, Cu_xTe_y composite anode materials were prepared using a microwave-assisted method and subsequently characterized using various techniques. The three-electrode performance of the material was tested using a 6 M KOH alkaline solution, and results showed that the multiple valence states of Cu element provided abundant redox active sites. These sites conferred the Cu_xTe_y electrode with excellent capacitance (708 mAh g⁻¹). Thus, symmetric supercapacitor devices were constructed with a power of 3056 Wh kg⁻¹ and an energy density of 73 Wh kg⁻¹ in a relatively superior position. The capacitance retention for 1000 consecutive charge–discharge cycles was 71.3%, and the Coulomb efficiency was 99.1%.