Bimetallic Zn/Cu Metal–Organic Framework (MOF)/ Two‐Dimensional i ‐MBene Hybrid Electrodes for Enhanced Supercapacitor Performance

ABSTRACT

We demonstrate a tunable organic/inorganic metal–organic framework (MOF) structure, constructed on in‐plane MBene ( i ‐MBene) to serve as electrodes for supercapacitors. Bimetallic Zn/Cu MOF was synthesized and hybridized in situ over in‐plane Mo _4/3 Y _2/3 B ₂ (ZC‐MYB), whereas i ‐MBene was produced by etching aluminum layers using hydrofluoric acid. The ZC‐MYB composite demonstrated a 46% increase in specific capacitance compared to ZC MOF and a 5.6‐fold increase over i‐ MBene at 1 A/g in hybrid (asymmetric) supercapacitors. The ZC‐MYB composite exhibited an 81% cyclic durability over 9000 cycles. The apparent diffusion coefficient of ZC and ZC‐MYB obtained from the Warburg element decreased, while electrochemical impedance analysis exhibited a much lower polarization resistance and a CPE response closer to the ideal capacitive behavior in 6 M KOH. The ZC‐MYB/AC device, operating as an asymmetric supercapacitor, demonstrated a specific capacitance of 73.4 F/g at a scan rate of 2 mV/s and maintained a voltage window of 1.6 V. A Random Forest model trained on 200 experimental observations from 35 independently synthesized samples showed a moderate within‐domain prediction ( R ² = 0.522), under a leave‐one‐sample‐out validation. However, very low prediction of the high specific capacitance data illustrated the role of the model as an exploratory, rather than a universal predictor.