Cobalt Metal–Organic Framework as a Standalone Material for Supercapattery Electrodes: Achieving Superior Power Density among Advanced Energy Storage Devices

Supercapatteries or hybrid energy storage devices are a promising solution to the energy crisis. An efficient supercapacitor must show high power and energy density, along with excellent cyclic ability and good capacitance retention. However, it is quite challenging as most materials either suffer from a lack of redox-active sites or low surface area values or stability. The current work reports a 2D cobalt MOF, Co[(2,6-NDC)(DPNDI)], as a free-standing electrode material for supercapatteries. The MOF shows a specific capacitance of 503 F g^–1, and a symmetric device achieves a maximum power density of 6433.25 W kg^–1, which is among the highest reported for any MOF-based hybrid device. Additionally, the device shows excellent cycling stability, retains 99.8% capacitance after 30,000 cycles, and can power LED bulbs, making it highly promising for future energy storage applications.