Electrochemical investigation of CuSe nanoparticles decorated over g-CN nanosheet for supercapacitor applications

The emergence of energy crisis in the world can be attributed to the rapid progression of industrialization. It is necessary to prioritize the development of autonomous high-capacity storage technologies that can effectively utilize renewable energy sources. CuSe has gained significant interest as an electrode material due to its superior specific capacitance (C_s) and flexibility. Nevertheless, its electrochemical functionality is hindered by slow ion transfers and the agglomeration of particles. For this purpose, the utilization of carbonaceous materials such as g-CN, which possess remarkable characteristics like 2D support, high nitrogen concentration and greater specific surface area (SSA), can significantly enhance electrical conductivity by reducing aggregation. Herein, we developed CuSe nanoparticles on g-CN nanosheets utilizing a simple hydrothermal approach. The synhesized material displays a maximum C_s of 1109 F/g which is significantly larger than pure CuSe (609 F/g) and g-CN (239 F/g) at same current density (C_d) of 1 A/g and retians 97.6 % of capacitance after 5000 charge-discharge cycles. As-prepared material demonstrated high specific energy (S_E = 54.82 Wh/kg) and specific power (S_P = 645 W/kg), accordingly. Besides, the fabricated CuSe/g-CN nanocomposite shows greater SSA (53 m²/g) with significantly lower charge transfer resistance (R_ct, 0.74 Ω). The favourable outcomes provide compelling evidence that metal selenides incorporated on g-CN can be efficiently employed as substitute electrodes in supercapacitors.