Self-rechargeable multifunctional carbon fiber composites with CNTs supercapacitors

Advances toward the development of light-weight fully electric aerospace structures lead to the need of replacing on-board batteries with lighter and more efficient energy storage devices and systems. Here a novel self-rechargeable multifunctional carbon fiber composite is presented. The composite has the capability to monitor internal (such as damage) and external parameters (e.g. flight conditions) with high accuracy, to provide the required energy to the embedded monitoring system as well as to other on-board equipment while keeping its structural integrity and strength, increasing its life-time and power capability and decreasing the global weight of the overall aerospace structure. The self-recharging capability is given by a series of miniaturized supercapacitor cells that are first prefabricated on a strategic support already integrated with the necessary circuitry and then are embedded in a cost-effective manner between the layers of the composite. Here it is also demonstrated that supercapacitor cells made with carbon nanotubes electrodes can become lighter and can provide superior performance by thinning its electrodes. For instance, going from 400μm to 20μm thick CNTs-electrodes a 1246% power increase, a 21% specific capacitance increase and a 60% electrode resistance reduction were recorded. Moreover the ultra-thin supercapacitors were found to provide these high performance responses with a reaction speed about 30% superior than ever reported in the literature and over an extremely wide frequency range (up to 10KHz).