钼掺杂二氧化锰电极材料的制备及其超电性能研究OA

The practical application of manganese dioxide(MnO2)in supercapacitors is limited by the difficulty of concurrently achieving high energy and power density.This study addresses this limitation through a"bottom-up"structural tuning strategy in which[MoO6]units,whose octahedral parameters closely match those of the host[MnO6],are introduced into the MnO2 lattice during hydrothermal synthesis to perturb[MnO6]octahedral assembly and enable precise structural modification.The[MoO6]concentration proved to be a critical parameter governing the resulting morphology,crystal phase,and defect density.Scanning electron microscopy(SEM)and transmission electron microscopy(TEM)confirmed pronounced morphological changes upon[MoO6]incorporation,while X-ray photoelectron spectroscopy(XPS)and high-resolution TEM(HRTEM)revealed the formation of additional oxygen vacancies and a disordered local structure.Electrochemical measurements showed that the optimally doped sample(Mo0.05-MnO2)achieved a specific capacitance of 158.9 F/g at 5 mV/s and retained 68％of this value at 200 mV/s.The role of[MoO6]in charge storage was further investigated by in situ electrochemical impedance spectroscopy,from which ion diffusion coefficients were determined for electrodes across a range of doping levels.Finite element analysis indicated that moderate[MoO6]doping produces a defect-rich yet locally ordered structure that optimally balances active-site density and ion diffusion relaxation time,thereby enhancing both energy and power density simultaneously.These findings establish a viable route for synthesizing high-performance Mo-doped MnO2 electrodes and clarify the underlying structure-performance relationship,offering design guidelines for advanced pseudocapacitive materials.