Derivation of a governing rule in triboelectric charging and series from thermoelectricity

Friction-driven static electrification is familiar and fundamental in daily life, industry, technology, but its basics have long been unknown continually perplexed scientists from ancient Greece to the modern high-tech era. Despite simple manifestation, triboelectric charging believed be very complex because of unresolvable interfacial interaction between two rubbing materials. Here, we for first time reveal a physics series based on friction-originated thermoelectric effects at interface, characterized by material density (${\rho}$), specific heat (c), thermal conductivity (k), Seebeck coefficient (S) each material. We demonstrate that energy dissipational interface induces temperature variations materials thus develops electrostatic potentials will initiate across interface. find trends quantities various polymers, metals, semiconductors, even lightning clouds are simply governed factor ${\xi}=S/\sqrt{{\rho}ck}$. The figure-of-merit expressed with power K=${\xi}\sqrt{t/{\pi}}$, which difference can maximized up 1.2 V/W cm$^{-2}$ friction t = 1 s. Our findings bring significant opportunities microscopic understanding management triboelectricity or electrification.