Mr. Ziv Arzi, M.Sc. Candidate
Faculty of Materials Science and Engineering
Technion – Israel Institute of Technology Haifa 3200003, Israel
The intermittent nature of solar and wind energies requires large-scale energy storage for grid balancing. Battery energy storage answers some of these challenges, but it is limited by low specific energy, slow charging and high cost, leaving plenty of room for other energy storage technologies such as water electrolysis for the production of hydrogen. To this end, high efficiency and low-cost water electrolysis technology must be developed. Electrochemical – Thermally Activated Chemical water splitting presents a promising approach for high-efficiency water splitting with decoupled hydrogen and oxygen production. It relies on the reversible redox reaction of nickel (oxy)hydroxide anodes that can be charged electrochemically while hydrogen is being generated at the cathode, and then regenerated in a chemical reaction with water that completes the water splitting reaction. The process efficiency and economic viability depend on anode properties such as the charging overpotential, regenerable charge capacity, stability and cyclability. This work examines the processing – microstructure – properties relationship in nickel (oxy)hydroxide anodes produced by electrochemical deposition on nickel foam substrates. The effect of process parameters on the anode microstructure was examined by SEM, XRD and micro-CT. Their electrochemical properties were studied through charge-discharge cycles, and the regenerable charge capacity and the charge and discharge time constants were obtained by fitting the results to a semi-empirical equivalent circuit model.