Flexible MXene-coated melamine foam based phase change material composites for integrated solar-thermal energy conversion/storage, shape memory and thermal therapy functions

The liquid leakage, low light absorption capability and strong rigidity severely limit large-scale applications of phase change materials (PCMs). In this work, novel PCM composites with good encapsulation property, superior solar-to-thermal conversion efficiency and shape memory function were fabricated by introducing MXene-coated melamine foam (MF@MXene) into poly(ethylene glycol) (PEG). The MF@MXene/PEG composites showed satisfactory dimension retention ratio (90%) and phase change enthalpy (194.1 Jg −1 ). The three-dimensional MXene network constructed along the MF skeleton imparted the PCM composites with the ability to absorb and store the solar-energy as latent heat. Sunlight irradiation measurements suggested that the solar-thermal conversion efficiency reached 92.7%. Moreover, combining the resilience of MF@MXene sponge and the phase transition of PEG, the PCM composites exhibited remarkable shape fixation and recovery effects. A flexible heat eye-patch was further developed, which could be closely attached on human eyes and provided long-time thermal comfort within a stable temperature range.