Enhanced thermal conductivity of phase change material nanocomposites based on MnO2 nanowires and nanotubes for energy storage

Phase change materials (PCMs) have been widely used as efficient materials in latent heat thermal storage systems for various applications. The poor thermal conductivity of most organic phase change materials (OPCMs), however, has long been considered as one of big obstacles hindering their practical applications. Here, we report the first examples of Manganese dioxide nanowires and nanotubes based PCM nanocomposites (named as MnO2 NWs/PCM and MnO2 NTs/PCM) with enhanced thermal conductivity by simply using MnO2 nanowires and nanotubes as efficient nanofillers. The PCMs nanocomposites show high latent heat ranging from 140.1 J g(-1) to 206.1 J g(-1). The thermal conductivity of PCM nanocomposites were dramatically enhanced by incorporation of Manganese dioxide nanowires and nanotubes with a maximum value of 377.16% of that of pure PA achieved, which is nearly two times of that of control. X-ray diffraction (XRD) analysis shows that the incorporation of nanofillers does not change the crystalline structure of OPCMs while lowering its crystalline size. The PCM nanocomposites also show excellent thermal stability of recyclability. Only a slight loss of 2.8% in latent heat was observed after 100 times of melting/cooling cycles. Based on their high heat storage performance, excellent thermal conductivity and thermal stability of recyclability, the as-prepared PCM nano composites may have great potentials for energy saving applications.