Tailoring thermal properties via synergistic effect in a multifunctional phase change composite based on methyl stearate

Organic phase change materials (PCMs) have poor conductivity and are naturally flammable. In this effort, we report a multifunctional phase change composite in which electro-to-thermal energy conversion could be realized by applying very small voltages as low as 1.4 V. Methyl stearate (MeSA) is used as the phase change material, with expanded graphite (EG) as the support, nano-organophilic montmorillonite (nOMMT) and ammonium polyphosphate (APP) as the flame retardants. Uniform interpenetration of PCM in the composite coupled with synergistic effect of the additives performs superb properties in improving the thermal stability and latent heat of composite. The thermal conductivity of the composite is increased up to 3.6 W m−1 K−1, while the thermal enthalpy is retained and an electro-to-thermal conversion efficiency of 72% is reached. Our tailored approach gives rise to a new avenue for practical application of PCM with facile preparation.