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Generating oxygen vacancies (Vö) in vanadium pentoxide (V 2 O 5 ) has been demonstrated as an effective approach to tailor its electrochemical properties. The present study investigates three different kinds of conductive polymer (CP = PPy, PEDOT, and PANI) coated V 2 O 5 nanofibers with Vö generated at the interface during the polymerization process. Surface Vö form a local electric field and promote the charge transfer kinetics of the resulting Vö-V 2 O 5 /CP nanocables, and the accompanying V 4+ and V 3+ ions may also catalyze the redox reactions and improve the supercapacitor performance. The differences and similarities of three different CP coatings have been compared and discussed, and are dependent on their polymerization conditions and coating thickness. The distribution of Vö in the surface layer and in the bulk has been elaborated and the corresponding effects on the electrochemical properties and supercapacitor performance have also been investigated. Vö-V 2 O 5 /CP can deliver a high capacity of up to 614 F g −1 at a current rate of 0.5 A g −1 and supercapacitors with Vö-V 2 O 5 /CP demonstrated excellent cycling stability over 15 000 cycles at a rate of 10 A g −1 . 

Li-ion diffusion and lithiation kinetics in MnO/C nanocomposites were systematically investigated by monitoring the change in the charge transfer resistance and the ion diffusion coefficient, and the kinetically predominant process at various charge/discharge states. Crystal field analysis and density functional theory (DFT) calculations were introduced to reveal the relationship between the electronic structure of the phase compositions, the displayed electrochemical potential and its profile. The split 3d orbitals in the Mn ion determine the ordering of the electron migration and energy difference, leading to the different potential profiles in the lithiated/delithiated process. The phase compositions strongly affect the intrinsic properties of the MnO/C nanocomposites, increasing the ion diffusion coefficient from ∼10 −15 to 10 −11 cm 2 s −1 when the electrode progressed from the fully charged to fully discharged state, while both the surface redox reaction and the solid-state diffusion could be the limiting process depending on the lithiation/delithiation states. In addition, the MnO/C anode delivers an energy efficiency of 90% in a Li-ion hybrid capacitor, suggesting a promising and competitive application in the future. 

Abstract A local electric field is induced to engineer the interface of vanadium pentoxide nanofibers (V₂O₅‐NF) to manipulate the charge transport behavior and obtain high‐energy and durable supercapacitors. The interface of V₂O₅‐NF is modified with oxygen vacancies (Vö) in a one‐step polymerization process of polyaniline (PANI). In the charge storage process, the local electric field deriving from the lopsided charge distribution around Vö will provide Coulombic forces to promote the charge transport in the resultant Vö‐V₂O₅/PANI nanocable electrode. Furthermore, an ≈7 nm porous PANI coating serves as the external percolated charge transport pathway. As the charge transfer kinetics are synergistically enhanced by the dual modifications, Vö‐V₂O₅/PANI‐based supercapacitors exhibit an excellent specific capacitance (523 F g⁻¹) as well as a long cycling lifespan (110% of capacitance remained after 20 000 cycles). This work paves an effective way to promote the charge transfer kinetics of electrode materials for next‐generation energy storage systems.