Flexible PW/PU@CuNWs-MXene composite phase change materials with high thermostability for superior solar-thermal energy storage

Phase change materials (PCM) possess the issues of leakage, low thermal conductivity, lack of rigidity and poor photo thermal conversion ability. To overcome these challenges, we have successfully designed and prepared flexible PW/PU/CuNWs/MXene (PPCuM) composite phase change materials with high thermal conductivity by solution blending and vacuum impregnation by using polyurethane (PU), one-dimensional copper nanowires (CuNWs) as high thermal conductivity, and two-dimensional transition metal carbide/nitride (MXene) as fillers. Furthermore, PU based PCM is developed by adding MXene at different weight fractions and the influence of MXene content on PPCuM properties was studied. As expected, benefiting from the high aspect ratio and strong capillary force of the MXene as well as the interfacial interaction between the PCM molecule and MXene, the resulting PPCuM exhibit a large thermal conductivity (0.705 W·m −1 ·K −1 ), which is 332.5% higher than that of pure PW, high latent heat (155.42 J·g −1 ), mechanical strength reaches 81.83 KPa, and are form-stable upon heating up to 75°C. The solar simulator and thermal conductivity demonstrated a superior photo-thermal conversion capability and thermal networks for the developed PU based composite sample at 83.3 wt% of MXene. At the same time, MXene effectively improved the photo-thermal conversion capacity (91.35%) and heat transfer rate (2.91 J·s −1 ) of PPCuM, which was further confirmed by the surface temperature distribution results. In addition, PPCuM has excellent photo-thermal conversion efficiency, good chemical compatibility, crystallization properties, and acceptable thermal stability.