Title: Effective thermal conductivity of La_0.9Ce_0.1Ni₅ metal hydride: effect of hydrogenation cycles, particle size and hydrogen concentration

Authors: Pyoungjong Lee; Kwangjin Jung; Kyoungsoo Kang; Seonguk Jeong; Ki Bong Lee; Chusik Park

Addresses: Hydrogen Research Department, Hydrogen Energy Institute, Korea Institute of Energy Research (KIER), 152 Gajeong-ro, Yuseong-gu, Daejeon 34129, Republic of Korea; Department of Chemical and Biological Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea ' Hydrogen Research Department, Hydrogen Energy Institute, Korea Institute of Energy Research (KIER), 152 Gajeong-ro, Yuseong-gu, Daejeon 34129, Republic of Korea ' Hydrogen Research Department, Hydrogen Energy Institute, Korea Institute of Energy Research (KIER), 152 Gajeong-ro, Yuseong-gu, Daejeon 34129, Republic of Korea ' Hydrogen Research Department, Hydrogen Energy Institute, Korea Institute of Energy Research (KIER), 152 Gajeong-ro, Yuseong-gu, Daejeon 34129, Republic of Korea ' Department of Chemical and Biological Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea ' Hydrogen Research Department, Hydrogen Energy Institute, Korea Institute of Energy Research (KIER), 152 Gajeong-ro, Yuseong-gu, Daejeon 34129, Republic of Korea

Abstract: 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 La_0.9Ce_0.1Ni₅ 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 La_0.9Ce_0.1Ni₅ 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.

Keywords: metal hydride; effective thermal conductivity; comparative radial heat flow method; hydrogenation; particle size; hydrogen concentration.

DOI: 10.1504/IJNT.2025.152226

International Journal of Nanotechnology, 2025 Vol.22 No.1, pp.2 - 16

Published online: 11 Mar 2026 *

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