Ahiud Morag

The increasing demand for flexible and wearable microelectronics is a major driving force for the development of high-performance small-volume energy sources. Microsupercapacitors exhibit significant potential in energy storage as they provide high power and good cycle stability. Yet, most microsupercapacitors display low energy densities limiting their practical use in microelectronics. Here, synthesis of high surface area freestanding electrodes comprising hollow nickel microfibers is demonstrated. The microfiber nickel electrodes constitute a platform for flexible asymmetric microsupercapacitors exhibiting excellent mechanical resilience as well as high energy density (0.11 mWh cm⁻²) and power density (37.5 mW cm⁻²). The freestanding nature and extensive surface area of the electrodes contribute to pronounced areal and volumetric capacitance, energy storage values, and stability after numerous (hundreds) physical bending cycles. The simple preparation scheme and use of an inexpensive building block (e.g., nickel) underscore potential uses as light and flexible energy storage devices.