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

Abstract

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 −1 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 −1 with a power density of 532 W kg −1 . 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 cuttingedge energy storage devices.

Novel composite of ZnMoO4/Ni(OH)2 as an electrode material for enhanced performance in energy-storage applications

“…3,4 Consequently, numerous efforts have been devoted to exploring and developing efficient electrode materials for PCs, such as transition metal-based oxides, hydroxides, sulphides, selenides/tellurides, conducting polymers, and their composites. 5,6 Among the various PC materials, nickel hydroxide (Ni(OH) 2 ) is one of the more versatile materials and has been widely investigated because of its battery-type charge-storage behavior, exhibiting a high theoretical specific capacitance of 2082 F g À1 . However, the structural instability demonstrated during cycle studies and the poor conductivity of Ni(OH) 2 prevent it from achieving a sufficient performance.…”

Tweaking the Efficiency of Asymmetric Hybrid Supercapacitors with Mechanochemically Synthesized Mixed‐Metal–Organic Framework‐Derived Metal Oxides

“…After the completion of the charge and discharge cycle, coulombic efficiency and energy efficiency from the GCD curve of the fabricated device can be calculated from the Equation (14). The energy efficiency was calculated from cycle stability according to Equation (15) [ 36 ] :…”

Electrochemical performance of a Li+-enriched metallohydrogel as an electrolyte and electrode material for supercapacitors

“…In addition, it is evident from the FE-SEM image that MG-Co has good porosity; thus, it could be a suitable choice as an electrode material with enhanced electrochemical behaviour. 25 Moreover, energy-dispersive X-ray and elemental mapping analysis jointly conrm the presence of uniformly distributed Co elements in MG-Co gel samples (Fig. 1 and S7, ESI †).…”