Electrochemical behavior of metal hydride electrode with different particle size

The behavior of the negative electrode in rechargeable alkaline Ni/MH batteries depends on factors such as hydrogen storage capacity, kinetics of processes occurring at the metal/electrolyte interface and transport of hydrogen within the bulk of the metal alloy. The particle size of the alloy is a parameter to consider during the design of the electrodes. The aim of this work was to study how the alloy particle size affects the electrochemical performance of the electrode. The electrodes were prepared using different particle size ranges and were characterized using basic electrochemical techniques (cyclic voltammetry, charge/discharge cycling, electrochemical impedance spectroscopy (EIS), and optical techniques (scanning electron microscopy (SEM)) that allowed to determine kinetic parameters of the hydriding reaction, transport of hydrogen in the alloys and structural electrode parameters. ► The particle size of the alloy is a parameter to consider during the design of the electrodes. ► The particle size influences the performance of the system. ► The particle size of the AB5 type alloy influences the capacity and the EIS response. ► AB2 alloys require longer activation times. ► SEM techniques allow to estimate the size of the particles.