Metal–Organic Framework‐Derived Anode and Polyaniline Chain Networked Cathode with Mesoporous and Conductive Pathways for High Energy Density, Ultrafast Rechargeable, and Long‐Life Hybrid Capacitors

Abstract Hybrid lithium‐ion energy storage devices are promising for future applications, but their anodes and cathodes still have structural limitations, for example, accommodating rich cationic/anionic reactions, rapid charge movement, and long cycle life. Herein, high‐capacity/high‐rate anode and cathode structures are developed to overcome these challenges. Molybdenum oxide (MoO 2 )‐implanted carbon frameworks making conductive carbon bonds with reduced graphene oxide (rGO) shells are developed as anode structures by forming mesoporous channels for fast lithium‐ion transport, carbon‐rGO pathways for facile electron conduction, and ultrafine MoO 2 units for high capacity. The operando X‐ray diffraction and kinetics analyses reveal that lithium‐ion insertion and extraction occur via capacitive and diffusion‐controlled reactions. Also, polyaniline (PANI) chains are elongated on rGO sheets through in situ polymerization to form crosslinked polyaniline chain‐integrated rGO as cathode structures. These display multiporosity for rapid anion transport, N‐doping sites for high capacity, and π–π bonding between PANI and rGO for electron conduction and cycle stability. Moreover, hybrid capacitors configured by this anode and cathode allow for the exploitation of battery‐type and pseudocapacitive reactions, as demonstrated by their extremely high energy density (up to 242 Wh kg −1 ), ultrafast chargeable power density (up to 28 750 W kg −1 ), and long‐life stability over 10 000 cycles.