All-fiber hybrid piezoelectric-enhanced triboelectric nanogenerator for wearable gesture monitoring

With the increasing potential of smart clothing, the demand for generating energy directly in the tissue fibers has prompted for increased research in the field of energy harvesters based on wearable nanogenerators. Current challenges remain in the combination of high output performance, functionalization, and importantly wearing comfort. Herein, an all-fiber hybrid piezoelectric-enhanced triboelectric nanogenerator fabricated by electrospinning silk fibroin and poly(vinylidene fluoride) (PVDF) nanofibers on conductive fabrics is presented. Due to the large specific surface area of nanofibers and the extraordinary ability of silk fibroin to donate electrons in triboelectrification, the hybrid nanogenerator shows outstanding electrical performance, with a power density of 310 µW/cm2. This novel all-fiber configuration provides all benefits of ordinary fabrics having flexible appearance and good air permeability, and moreover it can be custom embedded in clothes in any desirable size and shape. Furthermore, the fabricated device allows identifying various types of body motion by a correlation between gesture and corresponding electrical signal. As potential application field, we foresee an autonomous wearable fall alert microsystem for elderly people and persons working in high risk areas.