Fully self-powered electrocaloric cooling/heating with triboelectric nanogenerator

The annual energy consumption to supply traditional power for cooling or heating applications is tremendous. Refrigeration or heating technology that does not rely on traditional energy sources is of great interest for modern society to achieve energy conservation and emission reductions. In this work, we demonstrated a self-powered cooling and heating system, consisting of a triboelectric nanogenerator (TENG), a power and charging management module, and an electrocaloric (EC) material. Ferroelectric ceramics of 0.1 PbTiO3–0.9 PbSc0.5Ta0.5O3(PSTT) with high EC at room temperature were successfully prepared. By converting the TENG-harvested kinetic energy of the mechanical motion into electrical energy and applying or releasing a polarized electric field to 12 PSTT sheets through circuit management, we achieved excellent dual self-powered cooling/heating functions in the room-temperature range. When the operating frequency of the TENG was 3 Hz, in a space with a specific surface area ratio of only 3.328 % and a volume ratio of 0.433 %, a temperature change of 0.5 K was achieved within 5.5 min, and the energy conversion efficiency reached 10.926 %. Because the TENG can effectively harvest the kinetic energy of various motions, including body motions and widely distributed wind, water wave, and raindrop energy in nature, it can be used to develop compact, miniaturized, and self-powered solid-state cooling/heating devices based on the EC effect. With the advantages of a high coefficient of performance, ease of use, zero emissions and lack of pollution production, our proposed approach is expected to achieve widespread application in various fields.