High Quality Electret Based Triboelectric Nanogenerator for Boosted and Reliable Electrical Output Performance

The triboelectric nanogenerator (TENG) is in the spotlight due to its advantages of material and processing diversity. Despite these advantages, for its practical utilization, the output performance of the TENG still needs to be enhanced. Unlike most of the previous approach to increase triboelectricity between two contact surfaces, in this paper, the output performance is significantly enhanced by improving the electrical charge induction through employment of a stably pre-charged electret. The main advantages of the proposed strategy is stable long term output enhancement of the TENG. For the first time, the eminent concept of “quality of electrical charges” on the electret is proposed as the degree of helpfulness of the electrical charges to enhance the electrical output performance of the TENG. In this regard, a procedure to develop the electret with high quality electrical charges in deep traps, which determines long-term performance of the TENG, is systematically investigated to maximize the amount of electrical charges and simultaneously minimize their escape to the external environment. In consequence, unlike existing studies only focusing on immediate enhancement of electrical output performance of the TENG with electret, this study provides the strategy to stably enhance the output performance for a long time. This strategy becomes dominant especially with weak contact force generating small oscillation without strong contact between two materials. Thus, using the developed electret, enhanced and reliable performance of the energy harvester is further demonstrated as a proof of niche application to effectively harvest energy from weak vibration of an automobile engine.