Radical anion transfer during contact electrification and its compensation for charge loss in triboelectric nanogenerator

The triboelectric charge density is the core parameter of triboelectric nanogenerators (TENGs), which is usually suppressed by charge escaping. This work proposes a compensation method for suppressing charge escaping on triboelectric polymer by inducing radical ion transfer. Radical anions are injected onto the polytetrafluoroethylene (PTFE) to prepare ionized-PTFE (I-PTFE), which serves as a positive component to fabricate TENG together with fully charged dielectrics. In open air, the unprecedented charge density of 525 μC m−2 and 1237 μC m−2 are respectively realized with contact-separation and sliding mode TENG, which are much higher than that for the calculated threshold of air breakdown. The selective ion transfer on contact interface is demonstrated by secondary ion mass spectrometry, which accounts for the compensation of charge escaping. Hence, a strategy for maintaining ultrahigh charge density in atmosphere is summarized. The coexistence and complementarity of electron and ion transfer can also elucidate the mechanism of contact electrification.