A three-dimensional coupled structure triboelectric nanogenerator for vertical and horizontal mechanical energy harvesting and fitness gait monitoring

Recently, the self-powered monitoring device used for wearable sensors has attracted attention from various industries. It is worth noting that previous self-powered sensors were mostly focused on unidirectional sensing and monitoring, and few sensors can achieve both longitudinal and transverse sensing functions simultaneously. Here, we designed an arched and stacked coupling structure triboelectric nanogenerator (AS-TENG) to harvest horizontal and vertical mechanical energy. Meanwhile, the AS-TENG can simultaneously achieve sensing effects on longitudinal pressure and transverse pulling force. According to the results, the pulling force sensing sensitivity of AS-TENG can reach 2.415 V N−1, and the pressure sensing sensitivity of AS-TENG can arrive at 2.78 V N−1. Furthermore, under longitudinal 6 Hz mechanical motion excitation, the open-circuit voltage (Voc) and short circuit current (Isc) of AS-TENG can reach 28.21 μA and 173.25 V, respectively. The transfer charge (Qsc) of AS-TENG can arrive at 169.7 nC. The AS-TENG can achieve a maximum output power of 2.02 mW at a 3 MΩ load. Moreover, the sensing signal pulse width of AS-TENG can reach 180 ms, which is higher than the traditional arch structure’s 110 ms, indicating the unique advantages of AS-TENG in future fitness monitoring. This study provides a 3D triboelectric multi-directional sensor that will serve the fields of intelligent wearable fitness and sports.