Structural and thermal properties of paraffin-based graphene and carbon fibre composite phase change materials

Abstract

Given the energy crisis, decreasing resources of non-renewable energy, and environmental degradation by hydrocarbon-based energy, novel approaches must be designed. Phase Change Materials (PCM), which absorb and release heat during phase transition, are a suitable choice for battery thermal management systems. However, most pure PCMs possess poor thermal conductivity, limiting practical applications. Enhancing their thermal properties is crucial for effective utilization of them across a wide range of applications. This study focuses on improving PCM’s performance by incorporating carbon-based fillers, such as milled carbon fibres and graphene, into paraffin wax. Composite phase change materials were prepared with carbon filler loadings of 1–5 wt.% and 8 wt.%, 11 wt.%, and 14 wt.%, using methods such as sonication and magnetic stirring. Differential Scanning Calorimetry (DSC) and thermogravimetric analysis (TGA) were used to assess their thermal properties. Results showed significant improvements in thermal conductivity and stability with carbon fillers, though bulk heat capacity decreased slightly. Among the tested compositions, the milled carbon fibre-paraffin composite of 5 wt.% exhibited the highest thermal conductivity of 1.448 W m⁻¹ K⁻¹. The degradation temperature of paraffin increased by 10–30 °C with carbon-based fillers, depending on composition. DSC analysis showed phase change peaks between 30–40 °C (solidification) and 50–60 °C (melting), confirming the preservation of paraffin’s thermal properties. Overall, the findings of this study highlight the potential of composite PCMs in enhancing the performance of battery thermal management systems (BTMS), offering a promising avenue for future energy solutions through improved materials that can be promising for thermal management applications.