Direct current contact-mode triboelectric nanogenerators via systematic phase shifting

• Published in: Nano energy 2020-09, Vol.75, p.104887, Article 104887
• Main Authors: Dharmasena, R.D.I.G., Cronin, H.M., Dorey, R.A., Silva, S.R.P.
• Format: Article
• Language: English
• Subjects: Direct current nanogenerators; Distance dependent electric field model; Energy harvesting; Phase shift; Triboelectric nanogenerators
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2020.104887

The intermittency and discontinuous nature of power generation in Triboelectric Nanogenerators (TENGs) are arguably their most significant drawback, despite the promise demonstrated in low-power electronics. Herein, we introduce a novel technology to overcome this issue, in which, built-in systematic phase shifting of multiple poles is used to design a pseudo direct-current TENG. Unlike previous attempts of constructing near direct-current TENGs that are based on the segmentation of electrodes of a sliding mode TENG, this technology introduces a new method that depends on planned excitation of constituent TENG units at different time intervals to obtain the necessary phase shifts, achieved by their structural design that contains an asymmetric spatial arrangement. Therefore, the direct current generation for TENG, which was previously limited to the sliding mode TENG units, are expanded to contact-mode TENGs. The technology allows for continuous and smooth operation of the driven loads and paves the way for a new dawn in energy scavenging from mechanical sources. We use the distance-dependent electric field (DDEF) platform to design the systematic phase shifting technology, which is experimentally demonstrated via a free-standing mode TENG (FSTENG) based design, to power a number of prototype devices. The resultant power output of the TENG indicates a crest factor close to 1.1 at relatively low frequencies, the best reported values for TENGs with contact-mode basic units, to date. This work provides a route to the highly awaited solution to overcome the intermittency and sporadic nature of TENG outputs, thus, promoting the field towards powering next generation autonomous and mobile electronics. Triboelectric Nanogenerator is an emerging energy harvesting technology, however, the rapid variation of electrical outputs is seen as their most significant weakness. Herein, a novel technology to produce near direct current triboelectric nanogenerators is presented, applicable to a wide variety of device types and motion profiles. [Display omitted] •A novel method to construct a direct-current triboelectric nanogenerator (DC TENG) is shown via systematic phase shifting.•The DC TENG design depends on an asymmetric spatial arrangement of TENG poles and their engineered excitation.•This new method is compatible with various TENG designs and motion profiles, providing excellent output crest factors.