An Implantable Flexible Fiber Generator Without Encapsulation Made from Differentially Oxidized Carbon Nanotube Fibers

Stable and sustainable energy supply for wearable and implanted electronics is essential for the long-term and safe living body application. A biocompatible flexible wearable and implanted energy supply without encapsulation is urgently needed to meet the demand of body comfortability and safety. Here we report a flexible, lightweight and biocompatible fiber power generator made from two aligned carbon nanotube (CNT) fibers by modifying them with different oxygen-containing groups. The generator repeatedly produces electricity in various fluids ranging from stationary deionized water to biological fluids by controlling the switch on/off. The system sustains more than 100 discharge/recovering cycles without obvious decay in specific capacitance of 8.0 F/m 2 (4.5 F/g, 8.3×10 6 F/m 3 ). The recovered electricity generation is attributed to the control of the surface coverage of reactants on aligned CNTs when immersed into water during the conversion process from chemical energy to electricity. Its generality, easy fabrication and light weight are demonstrated to be promising for various applications that are highly desired while remain challenging currently, e.g. , in a mouse body to stimulate the nerve without encapsulation of the device