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

Novel electrode and electrolyte materials are crucial for enhancing supercapacitor efficiency. Metal–organic frameworks (MOFs) have gained attention owing to their high porosity and surface area. However, their low capacity limits their usage. To tackle this, a highly effective mechanochemical annealing strategy is implemented to improve their efficiency. Three different forms of metal oxides NiCo 2 O 4 are derived from bimetallic MOFs by incorporating Ni 2+ and Co 2+ with linkers 1,3,5‐benzene tricarboxylic acid (MO‐1), 2,6‐naphthalene dicarboxylic acid (MO‐2), and 1,2,4,5‐benzene tetracarboxylic acid (MO‐3). The synthesized metal oxides have different morphologies due to different linkers and displayed remarkable electrochemical performance, attributed to favorable charge transport paths and enhanced electrochemical double‐layer capacitance with an enlarged specific surface area. These metal oxides exhibit specific capacitance values of 913.3, 43.4, and 210 F g −1 at operating voltages of 0.55, 0.55, and 0.6 V for MO‐1, MO‐2, and MO‐3, respectively. Notably, MO‐1 shows extended discharging time and demonstrates the characteristic behavior of battery‐type supercapacitors, making it versatile. The fabricated hybrid supercapacitor (bimetal hybrid supercapacitor) shows pseudocapacitive behavior, reaching up to 1.5 V with a specific capacitance of 65.6 F g −1 , energy density of 73.83 W h kg −1 , and power density of 1181.2 W kg −1 .