Influence of kinetics of hydrogen transport in a metal hydride anode on the discharge properties of the Ni–MH batteries

• We propose a distributed model of discharge kinetics of metal hydride anode.
• The model fits the behavior of La2MgNi9La2MgNi9 alloy at various current densities.
• Fermi energy is shifted due to hydrogen concentration at the boundary.

We present a distributed mathematical model and fit discharge curves of Ni–MH anode made of new alloy La2MgNi9La2MgNi9. Conditions justified the single-particle approximation with the shrinking core morphology of the hydride phase. We used the connection between voltage on the MH electrode and hydrogen concentration in the solid solution near the electrolyte facing surface. This connection is based on shift of the Fermi energy of the metal due to hydrogen dissolution. The model takes hydrogen diffusion and free phase boundary into account. It can be built into more general models describing discharge of Ni–MH rechargeable batteries.