Highly conductive liquid metal electrode based stretchable piezoelectric-enhanced triboelectric nanogenerator for harvesting irregular mechanical energy

Triboelectric nanogenerator (TENG) and piezoelectric nanogenerator (PENG) present excellent performances in harvesting multivariant mechanical energy. However, the conductivity of electrode has become one of the important factors restricting the mechanical energy acquisition under the large deformation and multiple freedom degrees. In this work, a highly conductive stretchable electrode based piezoelectric-enhanced triboelectric nanogenerator (P-TENG) with outstanding performance is reported. Ultra-flexible silicone rubber based triboelectric part with surface modification and piezoelectric part with BaTiO3 dispersed possess excellent electrical and mechanical property, at the same time, the stretchable electrode based on liquid metal could maintain low resistance even under large deformation. The peak to peak open-circuit voltage (VOC) and short-circuit current (ISC) of P-TENG could reach 1.38 kV and 36.13 μA, respectively. The instantaneous power density can reach 1.1 mW/cm2 and the charge quantity in single capacitor charging circle is approximately 0.30 μC. It also has the surpassing force-electrical linearity that the output voltage positively correlating to stretching speeds and stretching rates. The resistance increments of electrode below 0.32 Ω under stretching rate more than 200% and the percentage of breaking elongation could reach 645%. In applying experiments, the P-TENG could directly light 16 LEDs and effectively identify the motion signals. This work provides a new thought for nanogenerator (NG) with high stretchability and applied to collect irregular mechanical energy. [Display omitted] •The resistance of electrode prepared by liquid metal is less than 2.0 Ω even under a tensile rate of 200%.•The output power density of piezoelectric-enhanced triboelectric nanogenerator could reach 1.1 mW/cm2.•The broken elongation of piezoelectric-enhanced triboelectric nanogenerator could reach 645%.•The nanogenerator could be used for mechanical energy collection and motional signals recognition.