Super-stretchable multi-sensing triboelectric nanogenerator based on liquid conductive composite

Stretchable triboelectric nanogenerators (TENGs) attract much attentions in the field of wearable electronics owing to their unique capabilities of ambient energy harvesting, especially from human activities, serving as sustainable power source as well as functional sensing device. The essential challenge of super-stretchable triboelectric nanogenerator (SS-TENG) is to overcome the non-stretchable drawback of conventional electrodes and endow them with remarkable extension capability. In this work, we developed a carbon nanotubes (CNT)-silicone rubber liquid composite with outstanding conductivity and fluidity, which provides an essential opportunity to realize a SS-TENG with the remarkable capability of 900% stretchable deformation. This newly developed SS-TENG successfully achieved the integration of bio-mechanical energy harvesting and multifunctional sensing. The electric output performance was comprehensively investigated and a maximum power density of 21.7 W/m2 was obtained, which is large enough to power common low-power-consumption electronic devices. As for passive sensing, the proposed SS-TENG can be utilized as a strain gauge with good sensitivity (gauge factor (GF) of 11.4) and low hysteresis (degree of hysteresis (DH) of 0.71%). Moreover, as for active sensing, the detection of dynamic motions of human body joints was realized due to the correlation between gesture and corresponding electrical signal. Eventually, a self-powered wearable keyboard based on SS-TENG arrays with outstanding conformability on curved surfaces was demonstrated, which reveals a promising potential of the proposed liquid conductive composite and the developed SS-TENG for self-powered wearable electronic applications, especially in the healthcare field.