Synthesis of Cobalt Diselenide Nanoparticles for the Integrated All-Solid-State Supercapacitors

The operating voltage and current through integrated devices are effective ways to explore the practical applications of supercapacitors. In this study, CoSe2 nanoparticles were fabricated by a facile hydrothermal method. As supercapacitor electrodes, CoSe2 nanoparticles exhibited a specific capacitance of 389.6 F g-1 at 1 A g-1. When CoSe2 served as a positive electrode for the asymmetric solid-state supercapacitor, it presented 47.4 F g-1 specific capacitance, 46.4 Wh kg-1 energy density with 1512 W kg-1 power density, and superior stability (92.06% capacitance retention after 3000 cycles). Especially, the integrated all-solid-state supercapacitors connected in series displayed the typical voltage extension capability (2.8 V for two devices in series), and the ones in parallel exhibited charge/discharge time expand capabilities (390 s for two devices in parallel). Therefore, the study shows the promising practical applications of CoSe2based supercapacitors for energy storage.

Automated summary

In this study, CoSe2 nanoparticles were synthesized and used as electrodes in supercapacitors. The CoSe2 nanoparticles exhibited excellent specific capacitance and stability, and showed typical voltage extension and charge/discharge time expansion capabilities in an asymmetric solid-state supercapacitor.