Compact passive thermal buffering enabled by a gallium-based shape stabilized phase change material under repeated high heat flux conditions

초록

Compact electronic devices subjected to repeated transient heat loads require passive thermal buffers capable of rapid latent heat recovery between heating events. Although gallium-based shape-stabilized phase change materials (SSPCMs) have been reported, quantitative links between material characteristics, device-level cooling performance, and system-level applicability remain limited. This study establishes an integrated material-to-device-to-system evaluation framework for a Ga/EG/ER SSPCM through material characterization, repeated chip-cooling experiments, and system-level assessment. Gallium served as the latent heat storage medium, expanded graphite provided continuous heat-transfer pathways, and epoxy resin stabilized the composite structure. The optimized SSPCM reduced the supercooling degree from 14.8 to 1.6 °C and shortened the recovery time from 36.9 to 20.0 s. After 500 thermal cycles between 80 and 5 °C, it retained approximately 99% of its initial mass together with 97.9% and 95.8% of its heating and cooling latent heat, respectively. Under the same-volume condition at 20 W/cm2, the gallium SSPCM reduced the maximum junction temperature from 65.1 to 34.8 °C and decreased the PCM-layer thermal resistance by 81.7% relative to octadecane SSPCM. Under the same-mass condition, the gallium thermal buffer was approximately 87% thinner while reducing the junction temperature by 13.3 °C. The junction temperature remained below 50 °C up to a heat flux of 20 W/cm2. System-level evaluation further demonstrated the feasibility of the proposed SSPCM as a compact, reusable passive thermal buffer for high-heat-flux electronics. These results provide a quantitative framework linking material properties to device-level cooling performance and system-level applicability. Copyright © 2026. Published by Elsevier Ltd.

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