In recent years, the growing demand for energy in human society has led governments to invest heavily in sustainable and renewable energy sources. With the emergence of new technologies and the use of green energy, such as hydrogen as a fuel, the issue of hydrogen storage has gained significant importance. Hydrogen as a secondary clean energy can lead to the development of fuel cell technology. Herein, we used an eco-friendly method for the as-preparation of brownmillerite-type Ca2Co2O5 nanopowder, to study the electrochemical of specific capacitance and hydrogen storage properties of the sample. Therefore, Ca2Co2O5 nanopowder is studied in terms of structure, surface morphology, physical properties, and electrochemical performance in energy storage. The electrochemical behaviors were evaluated through Cyclic Voltammetry (CV), Chronopotentiometry (CP), and Electrochemical impedance spectroscopy (EIS) analyses. The specific capacitance and an energy 1 1 density of Ca2Co2O5 in 1 M KOH (903 Fg and 125.416 Wh kg ) and in 1 mM K4 [Fe(CN) 6 ] +1 M KOH 1 1 electrolytes (1966 Fg and 273.05 Wh kg ) are calculated. Additionally, the chronopotentiometry results -1 showed that the Ca2Co2O5 nanopowder has a suitable discharge capacity of 2274 mAhg .
