Modeling and analysis of the friction in a non-linear sliding-mode triboelectric energy harvester

Friction plays a pivotal role in the sliding-mode triboelectric energy harvester (TEH), which not only enables the charge transfer between two dielectrics, but also influences the energy harvesting performance by affecting the dynamic response of the TEH. How to evaluate the effects of the friction on TEHs is important for optimizing TEHs in engineering practices. In order to analyze the effects of the friction on the dynamic response and evaluate the energy harvesting performance of TEHs, the paper models the friction of a devised non-linear TEH based on the Coulomb friction model and the Macro-slip friction theory. The TEH equips a pair of magnets, rendering a switching between the bistability and the monostability by tuning the distance between two magnets. The dynamic model of the non-linear TEH is established by the extended Hamilton principle. The effects of friction in sliding-mode TEH are dissected in detail. The influences of parameters on both the mechanical and electrical responses are also systemically studied to explore an optimal energy harvesting performance in the low-frequency range. This work provides a guideline for designing and accurately analyzing a sliding-mode TEH.