Dual-Function Coaxial Supercapacitor Cable

Developing lightweight, space saving, and multifunctional integrated device has become a critical task for numerous fields including displays, military and aviation. Components like electrical cables and supercapacitors have been widely and separately used as connectors and energy storage devices, respectively for many applications. Here we demonstrate a novel device architecture to develop an integrated coaxial supercapacitor cable (CSC) that functions both as electrical cable and energy storage device. Similar to typical coaxial cables, the inner core is used for electrical conduction and overlying layer is used for energy storage. A template-free method was developed to fabricate large area, high aspect ratio, nanowhisker-structure based cable electrodes. This unique design provides high specific capacitance (1,376 F g^-1) and exceptional reversible redox reactions for CSC electrodes. The integrated CSC device shows excellent flexibility and bendability, long and stable cycle lifetimes, and high energy and power densities. All these remarkable results demonstrate that CSC design can be very promising to club electrical conduction and energy storage into one cable for many technologically critical applications.