Energy Enhancement of a Nickel-Cobalt-Mixed Metallic Metal-Organic Framework Electrode and a Potassium Iodide Redox Mediator Bound with an Aqueous Electrolyte for High-Performance Redox-Aided Asymmetric Supercapacitors.

Enhancing the energy density of a supercapacitor requires the use of novel electrode and electrolyte materials that can withstand high voltages and have rapid electrochemical kinetics. Pesudocapacitance, high energy density, and specific capacitance may be provided by electrodes and redox mediator electrolytes used in redox-aided asymmetric supercapacitor equipment (RAASC), which are essential for their practical implementation. In this work, the rod and microsphere structure of the Ni/Co-mixed metal-organic framework (MOF) positive electrode material was synthesized using the hydrothermal method. Because of the high proposition of active sites and fluent ionic channels created by the rod and microsphere structure, as-prepared Ni/Co-MOF materials were used as three different organic linkers. CNN-MOF material has a rodlike structure and good capacitance value, so we further increase the capacitance value that we introduced in a KI redox mediator bound with a KOH electrolyte, and in this combination, a high specific capacitance up to 612 F g was reached in a three-electrode system. Additionally, an electrical double layer capacitor nature of the graphite anode material with CNN-MOF as a cathode material and a KI redox mediator bound with the KOH gel polymer electrolyte was observed in the assembled RAASC. The RAASC device had reached a high energy density of 84.2 W h kg with a power density of 532 W kg. At the same time, it showed good cyclic stability and could retain 97.4% of initial capacitance after 11,200 charge and discharge cycles. This work demonstrates efficient fabrication of high-performing MOF electrodes, and the fabrication of KI redox electrolyte-constructed RAASC devices offers a novel window into the creation of cutting-edge energy storage devices.