Eutectic Diol-Acid Phase Change Composite Reinforced With Expanded Graphite for High Performance Thermal Management

A bio-based binary eutectic phase change material (PCM) composed of 1,10-decanediol (DDL) and sebacic acid (SEA) was developed for passive thermal management of electronic devices. The eutectic composition was optimized through theoretical calculations and experimental validation to achieve a high latent heat. Expanded graphite (EG) was incorporated as a highly conductive supporting matrix to fabricate DDL–SEA/EG composite PCMs (CPCMs). The thermophysical properties, shape stability, thermal cycling reliability, and thermal management performance of the CPCMs were systematically evaluated. Results demonstrate that the CPCM with 12 wt% EG achieves a thermal conductivity of 9.305 W·m⁻¹·K⁻¹ (16.5-fold enhancement) and a latent heat of 194.1 kJ·kg⁻¹, while maintaining high shape stability with negligible leakage. Furthermore, the CPCM retains 98.5% and 99.6% of its initial melting and solidification enthalpy after 200 thermal cycles. Thermal management tests using a simulated electronic heat source reveal that the DDL–SEA/EG CPCM prolongs the time to reach 80 °C from 285 to 1400 s (a 391% increase) and suppresses the steady-state operating temperature by 10.3 °C. These findings indicate that the DDL–SEA/EG CPCM effectively resolves the tradeoff between energy storage capacity and thermal conductivity, presenting a highly promising, sustainable material for advanced passive electronics thermal management.