Series to parallel structure of electrode fiber: An effective method to remarkably reduce inner resistance of triboelectric nanogenerator textiles

Flexible and stretchable electrodes have been extensively explored in recent decades, promoting remarkable advances in wearable electronics. However, for the foreseeable future it will be hard to achieve a level of conductivity of stretchable electrodes equivalent to that of metallic electrodes, which undermines the potential for practical applications, especially for fiber-shaped electrodes with long length/diameter. Herein, the basic physical concept of the small resistance of parallel circuits was applied to a triboelectric nanogenerator (TENG) fiber/textile to dilute the negative effects of the huge resistance of stretchable electrode fibers. As a demonstration of the concept, stretchable gel electrode-based fibers were woven into parallel multi-fiber TENG structures (parallel-teng), which significantly reduced electrode resistance compared to single long-fiber knitting TENG (GS-teng). The output current of parallel-teng showed an 11.8 fold enhancement compared to that of GS-teng owing to the decrease in the inner resistance by an order of magnitude. This work demonstrates an easy method to reduce the electrode resistance using parallel multi-fiber structures, which provide an approach for dealing with low conductivity electrodes in practical application. Furthermore, other wearable devices where there is the challenge of stretchable high resistance of electrode fibers, such as fiber batteries and piezoelectric fibers, could be inspired by this work because of the versatility of the physical concept.