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

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 Mo4/3Y2/3B2 (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 (R2 = 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.