What is the role of electrostatic induction in a TENG?

Electrostatic induction plays a crucial role in the operation of a Triboelectric Nanogenerator (TENG) by enabling the generation of an electrical current. After the triboelectric effect generates charges on the surfaces of the triboelectric materials, these charges induce an electric potential on the electrodes. Specifically, the charges generated on the triboelectric layers create an electric field, which influences the distribution of free electrons within the conductive electrodes. In a typical TENG configuration, one electrode is placed on the back of each triboelectric material. When the surfaces are separated, the electric field created by the triboelectric charges causes electrons to flow in the external circuit connecting the two electrodes. This flow of electrons is electrostatic induction. The amount of charge induced on the electrodes is directly related to the amount of triboelectric charge and the geometry of the device. As the distance between the triboelectric layers and the electrodes changes during the device's operation, the induced charge distribution on the electrodes also changes, driving the flow of electrons back and forth in the external circuit, thus generating an alternating current (AC). For example, in a vertical contact-separation TENG, as the two triboelectric surfaces separate, the negatively charged surface repels electrons in the adjacent electrode, causing them to flow to the other electrode, creating a current. Conversely, when the surfaces come back into contact, the electrons flow back to the original electrode, reversing the current direction.