Investigation of exfoliated graphite nanoplatelets (xGnP) in improving thermal conductivity of paraffin wax-based phase change material

Composite phase change materials (PCM) for latent heat thermal energy storage were made by mixing two different kinds of exfoliated graphite nanoplatelets (xGnP-1 and xGnP-15) into paraffin wax. Direct casting and two roll milling were used to prepare samples. The investigation on the thermal and electrical conductivity of nanocomposites with these two nanoplatelets was performed. Higher thermal conductivity of composite PCM can be achieved with nanofillers of larger aspect ratio, better orientation and lower interface density. The thermal physical properties of the nanocomposites were investigated by differential scanning calorimetry and thermal gravimetric analysis. It was found that the latent heat of the nanocomposites was not adversely affected by the presence of xGnP nanoplatelets and the thermal stability improved.

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► Exfoliated graphite nanoplatelets of two sizes (xGnP) were mixed with paraffin wax.
► Composite phase change material exhibits higher thermal conductivity with xGnP-15.
► Number density of nanofiller is the limiting factor in heat conduction.
► Latent heat of paraffin is slightly improved by xGnP.
► Thermal stability of composite phase change material is improved by xGnP.