CNT-functionalized electrospun fiber mat for a stretchable moisture-driven power generator

초록

With recent demand for next-generation wearable and stretchable electronics, development of reliable power systems that can accommodate the flexibility and stretchability of devices is necessary. Recently, a moisture-driven power generator (MPG) has been considered as one of the powerful candidates for providing energy to the next-generation wearable and stretchable devices. However, so far, currently developed MPG systems do not meet the stretchability requirements. Here, we report a stretchable MPG formed by layer-by-layer coating of carbon nanotubes on a stretchable electrospun fiber mat. By adding water to the stretchable MPG, an electrical double layer is developed at the interface between the carbon nanotubes and water. Transport of protons (H3O+) in water induces the movement of electrons in the carbon nanotubes, inducing a pseudostreaming current. The MPG of 1 cm x 2 cm with 10 mu L of deionized water generates a maximum open-circuit voltage (V-OC) of 419 mV, a maximum short-circuit (I-SC) current of 1.5 mu A, and a maximum power output of 320 nW, depending on the loading of the carbon nanotubes. In addition, 0.6 M NaCl solution enhances the generated V-OC (similar to 800 mV), maximum I-SC (13 mu A), and maximum power output of 10.4 mu W by supplying additional Na+ ions to the carbon nanotube surface and reducing the resistance of the device, respectively. Furthermore, MPG can generate a V-OC of 600 mV and an I-SC of 0.7 mu A even when stretched with a strain of 60%. The MPG reported here has the potential to be used as a reliable power generator for wearable and stretchable electronic devices.

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