Soft Tubular Triboelectric Nanogenerator for Biomechanical Energy Harvesting

A triboelectric nanogenerator (TENG), fabricated by soft materials with advantages of flexibility, stretchability, and water resistance, is a potential means for biomechanical energy harvesting. Herein, a soft tubular TENG (ST-TENG) is proposed, which is composed of a flexible conductive sponge as the inner electrode and a soft silicone tube as the dielectric layer with the helix outer electrode. The ST-TENG can be built in outsoles and harvest various biomechanical energy including pressing, bending, and twisting. The output performance of ST-TENG was thoroughly investigated and the surface charge density can reach to 175.4 mu C m(-2). The ST-TENG has stable and durable characteristics for 1.2 x 10(6) working cycles, 100 h soaking, and 5000 times bending. By walking or jogging with the ST-TENG tubes, several portable electronics such as thermometer, digital watch, and calculator can be continuously powered. The soft energy harvester in this work has made a significant progress in self-powered devices.