Dipolar Energy as an Electrical Power Source: Dipole Rotation in Solids Enables a New Source for the Triboelectric Generator

Herein, the concept of triboelectric generators using dipolar polarization energy as an electrical power source is introduced. Dipolar polarization energy is stored in dielectric films by rubbing, and is conveyed to external circuits for use during the depolarization process. Pyromellitic dianhydride-4,4'-oxydianiline polyimide films are used as a possible candidate for triboelectric generators, where polarization is formed by rubbing owing to the orientational alignment of polar molecular groups. The current-voltage measurements are used to evaluate the equivalent-circuit parameters of the generator. The current source Is is 0.07 nA at 30 degrees C, which is enhanced to 0.13 nA at 110 degrees C. It is indicated in these results that the depolarization process proceeds in a short time at higher temperatures, causing an increase in the current. Consequently, the maximum power increases from 18 nW (30 degrees C) to 33 nW (110 degrees C). The enhancement of the output power at higher temperatures well supports the idea of using dipolar polarization energy as a power source of triboelectric generators.