Shaped Photothermal Conversion Phase-Change Materials with Excellent Electromagnetic Shielding Performance and Flame Retardancy

Shaped photothermal conversion energy-storage materials are urgently developed to deal with the energy crisis and environmental pollution, and widely applicated in the fields of solar-thermal power, new energy vehicle power battery, and so on, in which the serious electromagnetic radiation affects its normal use. Meanwhile, frequently used organic phase-change materials are easily flammable, which greatly threaten the safety of life and property. Therefore, it is urgent to design shaped photothermal conversion and energy-storage materials with high electromagnetic interference (EMI) shielding efficiency and good flame retardancy. Herein, 2D graphene oxide sheets are simultaneously reduced and foamed by hydrazine, and a multifunctional F-reduced graphene oxide (rGO)/paraffin composite is prepared by vacuum impregnation method. When incorporating 40 wt% of F-rGO, the photothermal-conversion efficiency reaches 81.6%, the latent heat rate only reduces by 22.4%, and the change of phase enthalpy for the composites only decreases by 9.5% and after 10 thermal cycles. In addition, its EMI shielding efficiency is as high as 74.6 dB. Compared with pure paraffin, its heat release capacity, peak heat release rate, and total heat release are reduced by 50.1%, 52.0%, and 43.0%, respectively, due to the tortuous path and catalytic carbonization of F-rGO.