Boosting Power-Generating Performance of Triboelectric Nanogenerators via Artificial Control of Ferroelectric Polarization and Dielectric Properties

초록

Low output current represents a critical challenge that has interrupted the use of triboelectric nanogenerators (TNGs) in a wide range of applications as sustainable power sources. Many approaches (e.g., operation at high frequency, parallel stacks of individual devices, and hybridization with other energy harvesters) remain limited in solving the challenge of low output current from TNGs. Here, a nanocomposite material system having a superior surface charge density as a triboelectric active material is reported. The nanocomposite material consists of a high dielectric ceramic material, barium titanate, showing great charge-trapping capability, together with a ferroelectric copolymer matrix, Poly(vinylidenefluoride-co-trifluoroethylene) (P(VDF-TrFE)), with electrically manipulated polarization with strong triboelectric charge transfer characteristics. Based on a contact potential difference study showing that poled P(VDF-TrFE) has 18 times higher charge attracting properties, a fraction between two components is optimized. Boosting power-generating performance is achieved for 1130 V of output voltage and 1.5 mA of output current with this ferroelectric composite-based TNG, under 6 kgf of pushing force at 5 Hz. An enormously faster charging property than traditional polymer film-based TNGs is demonstrated in this study. Finally, the charging of a self-powering smartwatch with a charging management circuit system with no external power sources is demonstrated successfully.

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