Efficient encapsulation of organic phase change materials through Diels-Alder reaction and in situ assembly for excellent photothermal conversion and energy storage

• Synthesis of a novel OPCM-MATD with high enthalpy and good stability. • MATD was grafted onto GN via a solvent-free D-A reaction to form MATD grafted GN (GM) nanoparticles . • A DSM protocol was employed to achieve in situ self-assembly of TiO 2 @GM SSPCMs . • TiO 2 @GM SSPCMs has high latent enthalpy, smaller degree of subcooling, low leakage rate, excellent photothermal conversion efficiency and suitable antibacterial activities. • TiO 2 @GM SSPCMs has better application prospects in solar thermoelectric power generation applications. Latent heat storage systems based on organic phase change materials (OPCMs) are recognized as an efficient strategy for solar energy utilization. However, OPCMs face challenges such as leakage and limited sunlight sensitivity, hindering their wide application in energy storage. In this study, maleic acid ditetradecyl ester (MATD) was grafted onto graphene (GN) through a solvent-free Diels–Alder (D-A) reaction, forming MATD-grafted GN (GM) nanoparticles . Subsequently, a direct synthesis method (DSM) was employed to achieve in situ self-assembly of TiO 2 @GM shape-stabilized phase change materials (SSPCMs) in the D-A reaction suspension. This approach allows the encapsulation of OPCMs and the simultaneous formation of porous TiO 2 , effectively avoiding the encapsulation inhomogeneity caused by surface tension between the support material and OPCMs, while significantly reducing the leakage rate of TiO 2 @GM SSPCMs. The resulting TiO 2 @GM SSPCMs not only have high melting enthalpy (93.9 J g -1 ) and smaller degree of subcooling (3.2 °C), but also exhibits excellent photothermal conversion efficiency (96.5 %), ultra-low leakage rate (0.21 %) and suitable antibacterial activities. These materials demonstrated advanced photothermal conversion and thermal storage properties, enabling solar thermoelectric power generation applications with extended operational capacity even in dark conditions. This work provides valuable insights for designing multifunctional solar-driven thermal interface materials.