Performance enhancement of triboelectric nanogenerator by embedding tea-leaf powder in waste polystyrene

A triboelectric nanogenerator (TENG), which harvests electrical energy from ambient mechanical vibrations, has emerged as a potential alternative to battery for future energy autonomous sensors and wireless devices. In this paper, we report a very simple and cost-effective strategy to improve the performance of a waste-material-based triboelectric nanogenerator (TENG). Tea-leaf powder is used as the filler in waste polysyrene (WPS), derived from the waste packaging material by using a very simple process. TENGs are fabricated using the composite layer comprising varying concentrations of the tea-leaf powder in WPS (Tea@WPS) as the tribopositive layer and polytetrafluoroethylene (PTFE) as the tribonegative layer. It is found that a low concentration of the tea leaf powder, such as 5 %, produces the best performance with a peak voltage of similar to 1800 V, a surface charge density of similar to 180 mu C/m(2), and a power density of 61.25 W/m(2), which are approximately 4.5x, 2.8x, and 8x higher than that for a similar TENG in which no tea-leaf filler is used in WPS. Possible reasons for such huge performance enhancement are discussed. Although the performance of the device is degraded when exposed to high humidity level, it is found that the device restores it original performance when the humidity is reduced again. No degradation of performance of the device is observed for over 110 days in the same ambient condition.