Current collectors of carbon fiber reinforced polymer for stackable energy storage composites

Abstract

Energy storage structural composites combine the function of storing energy with that of bearing mechanical load. Electrode and electrolyte components can simply be laminated to fabricate composite energy devices. We advance here a sheet of carbon fiber fabric interlaced with epoxy resin as a bipolar current collector (CC), which becomes a component of bipolar electrode when coated with an active material and dried. The CC is quite light and its specific strength is an order of magnitude higher than the typical metal CCs. We also advance a sheet of glass fiber fabric, a separator, impregnated with a eutectogel electrolyte as a composite separator/electrolyte component. The ionic conductivity of the electrolyte is excellent over a wide range of temperature and is stable up to 100 °C. Composite supercapacitors are fabricated by alternate stacking of the two component sheets. They are used to verify the scalability of the energy device achievable by the simple lamination and to demonstrate the significant enhancement in the power and energy density attainable by reducing the device weight through the utilization of the bipolar CCs. Practical utility of the stacked supercapacitors is demonstrated.