Hydrothermal Carbon Doped Form‐Stable Inorganic Hydrate Salts Phase Change Materials with Excellent Reutilization

Abstract Form‐stable phase‐change materials (PCMs) are increasingly meaningful to thermal storage technology in various application environments. In this research, the eutectic hydrate salt mixture/poly(acrylamide‐ co ‐acrylic acid) copolymer (EHS/PAAAM) was synthesized as a form‐stable PCM, which satisfactorily solves the liquid‐state leakage problem, which has previously led to weakened energy transfer efficiency and heat storage capacity. The doping of hydrothermal carbon (HTC), HTC‐EHS/PAAAM effectively improved these deficiencies, and it additionally showed eminent stability with a weak supercooling effect. The results were confirmed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), and the mechanism analysis was studied using SEM, XRD, and FTIR spectroscopy In addition, HTC‐EHS/PAAAM possesses excellent recyclability after 101 thermal cycles. Compared to EHS/PAAAM, the thermal conductivity of HTC‐EHS/PAAAM increased by 43.9 % with the 1.5 wt % content of HTC.