Polyacrylamide phase-change gels based on doped MoS2-rGO for efficient solar energy photothermal conversion and storage

The slow heat transfer rate, leakage susceptibility, and low photothermal conversion efficiency of the phase change materials (PCMs) may limit their application in thermal energy storage. To tackle this problem, photothermal composites (MoS2-rGO) were prepared by hydrothermal synthesis method, and then polyethylene glycol6000 (PEG-6000) and MoS2-rGO composites were encapsulated in polyacrylamide (PAM) by free radical polymerization to form an integrated photothermal storage system. The melting enthalpy (Delta Hm) of the light-thermal phase change gel (LTPCG) was 140.9 J/g and the crystallization enthalpy (Delta Hc) was 134.8 J/g when the PEG6000 loading reached 85 %. After 300 cycles, the Delta Hm and Delta Hc were 137.7 and 132.1 J/g, respectively, which were 2.3 % and 2.1 % lower than the initial values, demonstrating excellent thermal storage durability. In addition, under simulated solar irradiation conditions, the MoS2-rGO composites were able to capture photons and rapidly transfer phonons with high efficiency, achieving a photothermal conversion efficiency of 87.5 %. The prepared composite PCM has excellent thermal storage and photothermal properties, which are of practical significance for the efficient use of solar energy.