Three-dimensional modeling of alternating current triboelectric nanogenerator in the linear sliding mode

Energy harvesting from mechanical motions has immense applications such as self-powered sensors and renewable energy sources powered by ocean waves. In this context, the triboelectric nanogenerator is the cutting-edge technology that can effectively convert ambient mechanical energy into electricity through the Maxwell's displacement current. While further improvements of the energy conversion efficiency of triboelectric nanogenerators critically depend on theoretical modeling of the energy conversion process, to date only models based on single-relative-motion processes have been explored. Here, we analyze energy harvesting of triboelectric nanogenerators using a three-dimensional model in a linear-sliding mode and demonstrate a design of triboelectric nanogenerators that have a 77.5% enhancement in the average power in comparison with previous approaches. Moreover, our model shows the existence of a DC-like bias voltage contained in the basic AC output from the energy conversion, which makes the triboelectric nanogenerators an energy source more pliable than the traditional AC power generation systems. The present work provides a framework for systematic modeling of triboelectric nanogenerators and reveals the importance of obtaining direct analytical insight in understanding the current output characteristics of the triboelectric nanogenerators. Incorporating our model analysis in future designs of triboelectric nanogenerators is beneficial for increasing the energy conversion power and may provide insights that can be used in engineering the profile of the output current of the nanogenerators.