Dipolar polarization as an energy source of tribo-electric power generator

Abstract

Dipolar polarization in solids is proposed as an energy source of a tribo-electric power generator. This power generator does not require periodic displacement of electrodes to induce electrical current, but transient current due to dipolar depolarization conveys polarization energy to external load R. Based on the dielectric physics approach, a rigorous mathematical solution of the transient current is obtained. The transient current is described using two time-constants, α−1 and β−1, which are functions of dielectric relaxation time τ, R, static capacitance of film Cs, and capacitance of film at optical frequency C∞, and it gives one current peak at time tmax=lnβαα−β. The theoretical maximum power of this generator is half of the dipolar energy stored in films P024CsA (P0: dipolar polarization, A: working area of capacitor), and it is achieved under matching condition CsR=τ (τ: dielectric relaxation time of solids). The equivalent electrical circuit of the power source is illustrated by using current source Is=P0τA and shunt conductance Gi=εsτAL (L: thickness of film). This power generator is available in electrical circuits for use by supplying dipolar polarization P0 in a cyclic manner with mechanical force, such as rubbing.