Waste-derived nickel oxide and selenide/selenite nanoparticles for energy-storage applications

Energy storage systems, particularly batteries, supercapacitors, and their electrode materials, have been the topic of substantial investigation due to the rising need for renewable energy and environmental concerns. Nickel selenide/nickel selenite nanoparticles (NS/NSO) and nickel oxide (NiO) were fabricated from local electroplating waste electrodes as a nickel source with a simple and benign one-pot approach. The optimal NiO, prepared from spent Ni electrode powder, accomplished a specific capacitance of 498 F g-1 at a 0.5 A g-1 current density and kept as 146 F g-1 at 5.0 A g-1 in the three-electrode configuration. In comparison, it is found that NS/NSO specific capacitance values were 895 F g-1 and 220 F g-1 at 0.5 and 5 A g-1 current densities, respectively. NS/ NSO electrode exhibits a greater specific capacitance than NiO electrode at a current density of 0.5 A g-1. After 5000 cycles, NiO and NS/NSO electrodes showed excellent electrochemical reversibility, with 91.5 % and 93.4 % capacitance retention, respectively. For Li-ion batteries, the NS/NSO material could maintain a high reversible specific capacity of 508 mAh g-1. The high-rate performance indicates that the NS/NSO nanoparticles can bear high stress during the lithiation/delithiation process. By utilizing waste in energy storage tools, we have created a path for effective waste management.