Measurement and analysis of effective thermal conductivity of LaNi5 and its hydride under different gas atmospheres

In this work, an ETC measurement cell based on the steady-state radial heat flow method was fabricated, and its reliability was validated by a commercial instrument. The ETCs of unactuated and activated LaNi5 powder beds were measured under various filling gases in the pressure range from 0.1 to 1.5 MPa. The experimental results show that the ETC of activated LaNi5 powder is much lower than that of the unactuated material due to the pulverization effect. The ETCs of unactuated and activated LaNi5 powder in helium atmosphere lie in the ranges of 1.04-1.63 W m-1 K-1 and 0.49-0.85 W m-1 K-1, respectively. Furthermore, the ETC increases with the increasing pressure and thermal conductivity of filling gas. The effects of hydrogen absorption and desorption on the ETC were investigated by step-by-step reaction, which depend mainly on the hydrogen concentration and expansion/constriction of MH particles. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

In this study, an ETC measurement cell based on the steady-state radial heat flow method was fabricated and its reliability was confirmed. The experimental results show that the ETC of activated LaNi5 powder is lower than that of unactuated material, and it increases with pressure and thermal conductivity of filling gas. The effects of hydrogen absorption and desorption on ETC depend on hydrogen concentration and expansion/constriction of MH particles.