DOI: https://doi.org/10.55373/mjchem.v28i2.48

Keywords: Metal hydride, phase change material, compressed expanded graphite composite, heat dissipation, thermal management, hydrogenation, thermal buffering

Abstract

Metal hydrides (MHs) are a promising medium for hydrogen storage due to their high gravimetric and volumetric capacities, as well as inherent safety advantages. However, the exothermic nature of hydrogen absorption presents significant thermal management challenges. Effective heat dissipation is critical to maintain optimal thermodynamic and kinetic conditions and ensure system safety. Integrating phase change materials (PCMs) into a metal hydride system offers a passive strategy for thermal regulation. This study systematically investigated how the thickness of a compressed expanded graphite-based composite PCM layer influenced thermal performance during MH hydrogenation. Variable-power electrical heating was employed to simulate the heat generated during the hydrogenation of lanthanum–nickel, based on its reported reaction kinetics and thermodynamic properties. Increasing the composite PCM thickness enhanced thermal buffering and reduced peak temperatures, whereas excessive thickness increased thermal resistance and decreased overall efficiency. A 5.0 mm PCM layer provided an optimal balance of heat transfer, latent heat storage, thermal management, and operational safety, supporting a compact and cost-effective system under the simulated conditions.