Exalted charge transfer mechanism through effective interfacial engineering of Mn-BDC MOF and PANI for hybrid capacitor

Mn-1,4 benzene dicarboxylic acid (BDC) MOF/Polyaniline (Mn-BDC MOF/PANI) composites have emerged as promising materials for hybrid capacitors due to their synergistic properties. In this work, we present a DFT-assisted design approach to enhance the hybrid capacity of the composites. We synthesized Mn-BDC MOF and PANI using solvothermal and chemical polymerization techniques, respectively, and then composited them using the sonochemical method. The Mn-BDC MOF/PANI composite exhibited a unique morphology with Mn-BDC MOF rods intertwined within the PANI matrix. Electrochemical characterization revealed superior energy storage performance of the Mn-BDC MOF/PANI composite, particularly in the negative potential window. Importantly, the composite-loaded graphite sheet electrode displayed a specific capacity of 356 mAh g^-1 at 1 A g^-1 and excellent cycling stability with 96.6 % capacity retention after 10,000 cycles. Density functional theory (DFT) calculations further elucidated the detailed charge transfer mechanism at the Mn-BDC MOF/PANI interface, highlighting the enhanced electronic states near the Fermi level in the composite, contributing to its improved capacity. The Mn-BDC MOF/PANI||AC asymmetric hybrid capacitor delivered an energy density of 359.4 Wh kg^-1 and a power density of 1556 W kg^-1, demonstrating its potential for practical energy storage applications.