Crystalline Framework Electrodes for Hybrid Supercapacitors: Device‐Oriented Design From Metal–Organic and Covalent Organic Frameworks to Practical Hybrids

Hybrid supercapacitors (SCs) aim to combine battery-like energy with capacitor-like power. However, progress is limited by electrode designs that trade capacity for slow kinetics, unstable interfaces, and poor areal or volumetric performance. This review examines crystalline framework electrodes, including metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), as well as framework-derived materials, which combine ordered porosity with programmable redox chemistry. We develop a device-centered decision framework that links building-block chemistry and topology to charge-storage mode, ion transport, electrode density, and dominant failure pathways under two-electrode operation. We benchmark MOFs, COFs, composites, and derived phases across aqueous, organic, ionic-liquid, and gel electrolytes. We define minimum diagnostics to distinguish double-layer capacitance, surface-redox pseudocapacitance, and battery-like behavior in hybrid devices. To support translation from laboratory tests to practical electrodes, we synthesize strategies for conductivity and stability, including percolation-network design, pore-access engineering, conformal interface stabilization, and controlled reconstruction or derivatization, thereby broadening operating windows while suppressing dissolution, pore flooding, and impedance rise. Finally, we map degradation modes to mitigation levers and propose a fair-comparison checklist that prioritizes realistic mass loading, electrode density, and areal and volumetric metrics, enabling more durable, device-ready hybrid SCs.