Superior Instant Heating and Electrothermal Performances of Interconnected Graphene-Expanded Graphite-Based Electric Heating Composite

Electric heating composites play an important role in the rapid temperature response and electric-thermal conversion of instant electric heating tubes. However, the preparation of an electric heating composite with superior electrothermal performance and high-power density for high-temperature applications above 300 °C remains a challenge. Herein, a high-temperature electric heating composite was prepared with continuous fluffy three-dimensional interconnected graphene-expanded graphite hybrid conductive fillers (GGCF). A maximum temperature of 310 °C and a high heating rate of 450 °C·min–1 can be obtained in the PI electric heating film along with a high electrothermal radiation conversion efficiency of 44% and electrothermal conversion efficiency of 0.27 W·°C–1. The corresponding steady-state temperature is 5.1 and 12.7 times higher than those with equivalent alone rGO and alone GP, respectively. Furthermore, the final Al electric heating tube can heat the flowing water to 100 °C within 6 s at a typical water flow rate of 380 mL·min–1 and 2000 W. The 2 h continuous heating demonstrates long-term stability with a power fluctuation below 3%. 770 cycles of heating and cooling verify the excellent heat shock resistance and repeatability. The superior electrothermal performance, instant heating function, long-term stability, and high safety of this electric heating composite show great potential in electric heating fields.