Tribopositive biomass toward enhanced stretchability and ionic conductivity of energy harvesters and sensors

Abstract

At present, there is a rapidly growing demand for high-performance energy harvesters as power supply for wearable devices. Herein, an advanced tribopositive biomass film is developed by tuning the hygroscopicity and chelation of sodium carboxymethyl cellulose (SC) for use in triboelectric nanogenerator. The electrostatic ionic cross-linking of CuCl2 and SC and the hygroscopic plasticizing of glycerol increase the stretchability and electrical conductivity of SC by 47.8 and 7.5 × 103-folds, respectively. Given the trapped water content and chelation density, significantly improved tribopositivity, open circuit voltage (160 V), charge quantity (125 µC·m−2) and short-circuit current density (68.8 mA·m−2), representing an increase by 10, 10.9, and 28.8-folds, respectively. Further, the power density reaches 5.35 W·m−2, being higher than most biomass-based devices. Given the high electrical conductivity, the SC film also functions as current collector, thus avoiding the delamination issue in long-term device operation. In addition, the significantly enhanced stretchability of SC (430% of elongation at break), makes it an ideal candidate for wearable devices for effectively harvesting the energy from human motion while monitoring the relative humidity, thus paving the way toward sustainable alternatives for high performance wearable devices.