Quasi-Solid-state Li-ion Hybrid Capacitor Based on a Colloidal Metal-Organic Framework Interwoven by In-situ Polymerized PANI

Metal-organic frameworks (MOFs) have emerged as promising candidates for advanced energy storage systems. However, their practical application is hindered by intrinsic conductivity limitations. This study introduces a novel in-situ gel-confined polymerization strategy to fabricate MOFs gel/polyaniline (MOG/PANI) composites with precisely tunable architectures. Systematic adjustment of PANI content elucidates critical composition-property relationships, where the optimized MOG/PANI-3 composite exhibits uniform component distribution and enhanced interfacial interactions. The developed electrode exhibits an impressive specific capacitance of 423.8 F g-1 at a current density of 1 A g-1. Electrochemical studies showed that excessive incorporation of PANI induces detrimental aggregation phenomena that degrade impedance characteristics. The study developed a quasi-solid-state Li-ion hybrid capacitor using MOG/PANI-3 cathode paired with activated carbon anode. This configuration achieves an exceptional energy density of 41.3 W h kg-1 at 900 W kg-1. Furthermore, it maintains 87.3% capacitance retention after 4000 cycles at 5 A g-1, demonstrating acceptable cycling stability. This gel-confined synthesis method effectively addresses the poor conductivity issues inherent in MOFs-based electrode materials. Simultaneously, it creates a flexible platform for developing multifunctional hybrid materials tailored to next-generation energy storage systems.