Kirkendall Effect\nInduced Ionic Liquid-Assisted Metal−Organic\nFramework-Derived NiCo-P Electrode and Redox Electrolyte: Their Synergistic\nInterface Enhancing the Supercapacitor and Hydrogen Evolution Reaction\nPerformance

Enhancing the performance of electrodes and electrolytes\nusing\nionic liquids (ILs) is a promising avenue for energy storage and conversion,\nyet it remains a significant challenge. In this comprehensive study,\nwe highlight the crucial role of ionic liquids in the dual functionality\nof electrodes and electrolytes. Herein, NiCo-P derived from the metal−organic\nframework is synthesized with the assistance of 1-butyl-3-methylimidazoliumbis(trifluoromethylsulfonyl)\nimide (BMIM TFSI) ionic liquid, which induces the Kirkendall effect\nand results as a structural modifier. Additionally, the BMIM TFSI\ninteracts with the KOH electrolyte to form π−OH interactions,\nfacilitating fast reversible redox reactions at the electrolyte−electrode\ninterface. The as-prepared NiCo-P electrode combined with the BMIM\nTFSI electrolyte delivers a high specific capacitance of 821 F g<sup>−1</sup> at a current density of 1 A g<sup>−1</sup> in a three-electrode system. The assembled IL-aided hybrid supercapacitor\nproduced a high window potential of 1.4 V, a minimum energy density\nof 75.29 Wh kg<sup>−1</sup>, and an excellent stability performance\n(97.9% after 12000 cycles). Furthermore, the NiCo-P electrocatalyst\nexhibited a low overpotential (99 mV at 10 mA cm<sup>−2</sup>) and small Tafel slope value (77 mV dec<sup>−1</sup>) for\nhydrogen evolution reaction in the IL-bound KOH electrolyte. This\nstudy introduces a novel perspective on ionic liquids, which serve\ndual roles as both electrodes and electrolytes. This dual functionality\nsynergistically enhances energy storage capacity and catalytic efficacy.