Sustainable and shape-adaptable liquid single-electrode triboelectric nanogenerator for biomechanical energy harvesting

With the rapidly increasing health and environmental awareness, demands for wearable electronics are no longer limited to performance and design, but also safety, health and environment protection. Herein, a sustainable and shape-adaptable skin-like liquid single-electrode TENG (LS-TENG) is developed using aloe vera gel (AVG)@NaCl as the liquid electrode. As an effective network channel for charge transfer, the liquid electrode shows high conductivity and mobility, leading to a high current density that is 2.1–23 folds of reported LS-TENGs. Besides, the size effect of liquid electrode in LS-TENG is firstly investigated, upon which the output parameters are optimized. Consequently, AVG@1wt%NaCl-based LS-TENG shows the highest output reported for LS-TENG with V_OC of 157.8 V, J_SC of 44.2 mA/m² and power density of 4.61 W/m². Moreover, the device shows a high sensitivity to minute face expressions and is suitable for 2D or 3D-shape fabrication, indicating a great potential for use in wearable electronics, such as e-skin and health monitoring.