Energy conversion system based on Curie effect and triboelectric nanogenerator for low-grade heat energy harvesting

Low-grade heat energy offers an abundance quantity of energy, but the limitation of existing techniques makes it difficult to be harvested and utilized. Here, a useful method of heat energy harvesting is proposed to realize the energy conversion of heat energy-mechanical energy-electric energy via coupling with the Curie effect of ferromagnetic material, triboelectrification and electrostatic induction effect. Taking advantage of the phase transition between ferromagnetic and paramagnetic under external magnetic and thermal fields, the ferromagnetic material achieves automatic reciprocating movement between cold and hot zones, and thus drives the triboelectric nanogenerator (TENG) to run, which realizes the conversion of heat energy into electric energy. Meanwhile, in a reciprocating motion, the transferred charges of 325 nC can be obtained, and automatic operation can be realized continuously. This work not only demonstrates a useful process to achieve low temperature difference and fluctuating heat energy harvesting or sensing, but also broadens the application fields of TENGs.