Nickel oxide (NiO) nanoparticles (NPs) were successfully synthesized by utilizing the waste shell powder of Prunus dulcis (almond) through a simple, environmentally sound, cheap, and novel green approach. The almond shell powder was used as a stabilizing and reducing agent for the synthesis of NiO nanoparticles from NiNO₃.6H₂O solution at 60 ºC and pH 12. FTIR studies verified the synthesis of NiO NPs by the appearance of a characteristic vibrational peak at 611.97cm^-1 whereas an absorption peak at 267 nm appeared in the UV-Visible spectrum. However, the XRD and SEM analyses have shown the amorphous nature of synthesized NiO NPs. The cyclic voltammetry (CV) curve of NPs clearly indicated the redox reaction and the reversible behavior of NiO NPs. The galvanostatic charge discharge (GCD) curves have shown a higher charging time as compared to the discharging time.