Fig. 3From: Metal Electrode Polarization in Triboelectric Nanogenerator Probed by Surface Charge NeutralizationPolarization model experiment of the metal electrode in the electric field. a The process of net charge in metal polarization and b metal’s surface voltage. c The charge density of the metal generated by the electric field [1] and the net charge is generated [4] according to the distance from the plate electrodeBack to article page