In this work, we successfully prepare NiAl2O4/NiO nanocomposite with thermal decomposition method by using green tea extract (GTE) as precipitating agent. The biosynthesized NiAl2O4/NiO nanocomposite characterize using X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), N2 adsorption (BET), ultraviolet–visible (UV–Vis) spectroscopy, and transmission electron microscopy (TEM). Also, we study the electrochemical hydrogen storage properties of NiAl2O4/NiO nanocomposite porous with different calcination temperature. The discharge capacity of samples with calcination temperature 700, 800 and 900 °C are 450, 325 and 800 mAh/g after 15 cycles, respectively. Display omitted •NiAl2O4/NiO nanocomposition has been prepared using simple thermal decomposition method.•The effects of calcination temperature on morphology, size and optical properties were investigated.•The green tea extract can be used as precipitating agent.•For the first time, the hydrogen storage capacity of NiAl2O4/NiO was studied.