Fig. 6: Mechanism of MXenes lubricants on output performance of TVNGs.

a Mechanism diagram illustrating the enhancement effect on SS-TVNG induced by solid-liquid contact. b Band structure diagram of the p-n junction in the device, showing the influence of frictional electric field and interface resistance. c Optical images of fresh TVNGs, and TVNGs after stability tests without and with MXene lubricants (Scale bar: 500 μm).