Effective thermal conductivity of La0.9Ce0.1Ni5 metal hydride: effect of hydrogenation cycles, particle size and hydrogen concentration

Metal hydrides store hydrogen in a solid state through reactions with hydrogen, offering high storage density and safety as key advantages. Metal hydrides release heat during hydrogenation and absorb heat during dehydrogenation. To enable hydrogenation or dehydrogenation, it is important to promptly remove the heat generated during hydrogenation or supply the heat required during dehydrogenation. The effective thermal conductivity of the metal hydride is used to predict and evaluate the heat transfer performance, including both heat removal and supply. This study presents the effective thermal conductivity of La0.9Ce0.1Ni5 metal hydride as influenced by hydrogenation cycles, particle size, and hydrogen concentration. An effective thermal conductivity measurement device based on the comparative radial heat flow method was designed and fabricated to perform the measurements. The effective thermal conductivity of La0.9Ce0.1Ni5 metal hydride decreased with increasing hydrogenation cycles. It is expected to converge to 1.29 W/m·K after 23 cycles. With hydrogenation cycles, both the particle size and the effective thermal conductivity showed a similar tendency. With hydrogen concentration, the effective thermal conductivity variations of the metal hydride showed a similar tendency to the equilibrium pressure variations in the pressure-composition-temperature (PCT) curves.