Low-Cost Lightweight Carbon Foam/Paraffin Composite Phase Change Material with Enhanced Thermal Conductivity for Lithium-Ion Battery Thermal Management

Phase change materials (PCMs) are passive cooling media for lithium-ion battery thermal management owing to their high latent heat capacity and operational reliability. However, their practical implementation remains hindered by low thermal conductivity and leakage during phase transition. Herein, we report a lightweight and low-cost shape-stabilized composite PCM fabricated by impregnating paraffin into a porous carbon foam scaffold derived from commercial melamine foam. The interconnected carbon framework provides structural confinement to suppress paraffin leakage while establishing continuous heat-transfer pathways that markedly enhance thermal transport. The optimized composite (PCM-800) exhibits a low density of 0.89 g cm −3 and an ultralow material cost of ~0.0097 USD g −1 , substantially lower than those of conventional metallic-foam-based composites. Benefiting from the conductive carbon network, PCM-800 achieves a thermal conductivity of 0.52 Wm −1 K −1 , representing a 2.3-fold enhancement over pristine paraffin, while maintaining a high melting latent heat of 234.61 J g −1 and a phase transition temperature of 47.78 °C. Battery module tests demonstrate that PCM-800 maintains the cell temperature below 60 °C for 3750 s at 18 V, 1200 s at 22 V, and 550 s at 26.8 V, extending the safe operating time by 20% and 71% relative to pure paraffin and natural air cooling, respectively.