Energy & Fuels, Vol.35, No.1, 898-904, 2021
Microwave-Heated Graphene Realizes Ultrafast Energy Conversion and Thermal Storage
Thermal energy storage using common phase change materials (PCMs) usually suffers from a long time consumption, uneven temperature, and low efficiency. An electromagnetic induction heating method with the advantages of rapidness and heating from the inside out might mitigate these issues. Two-dimensional graphene owns a single atomic layer structure and a large number of exposed chemical bonds; therefore, making fast electromagnetic wave absorption and thermal conduction becomes possible. Herein, we realized a fast, uniform, and repeatable thermal conversion through microwave heating graphene and paraffin composite. Graphene acts as a bridge for linking microwaves and paraffin. It absorbs microwaves as a result of the existence of microenergy levels and transmits energy to paraffin in the form of thermal energy. As a consequence, the composite can be rapidly heated to the phase transition temperature (58 degrees C) within 1 min and the thermal effect can be maintained after 30 cycles. The enthalpy of composite is 190.04 J g(-1), even with 1 wt % loading of graphene. Moreover, this method can be safely handled in the air because the composite has almost no mass loss below 159.9 degrees C. In summary, the proposed strategy of microwave-heated graphene-PCMs has great application potential in thermal management and energy conversion.