Robust and flexible wearable generator driven by water evaporation for sustainable and portable self-power supply

A power supply with sustainable stability and flexibility is pressing demanded for the development of self-powered flexible wearable electronics devices. The nanogenerators driven by water evaporation has been proved to be a promising low-cost energy harvesting strategy for directly converting ubiquitous, green and renewable ambient thermal energy to electricity. Here, a novel hybrid strategy was proposed for wearable evaporation driven nanogenerator with high performance in flexibility, adhesion stability, portability, and sustainable electricity generation. Hybrid precursors by tactfully mixing oxide nanoparticles, glass fiber and polyvinylidene fluoride (PVDF) are printed on the flexible substrate. PVDF with three dimensional mesh structure plays a key role in ensuring adhesion between nanoparticles, and also keeping part of the surface of nanoparticles exposed for electricity generation. A sustainable open circuit voltage of 1.5 V and short circuit current of 1.45 μA was achieved for an individual nanogenerator. The output performance does not change obviously even after repeated flushing by water flow and large-scale bending deformation. Remarkably, as an example of application, the hybrid nanogenerator with water storing material worn on the model can continuously drive the electrical watch to work during the model walking. Our achievement provides an effective strategy for the stable application of wearable nanogenerator driven by water evaporation, and will be greatly beneficial to the field moving forward.