Preparation and supercapacitor performance of La-doped Fe2(MoO4)3@CoMoO4 core–shell structure

Abstract

In this study, La–Fe₂(MoO₄)₃@CoMoO₄ composite core–shell structured electrode materials were successfully prepared by the hydrothermal method. The research results show that the introduction of lanthanum not only enhances the conductivity and charge transfer rate of Fe₂(MoO₄)₃@CoMoO₄, but also improves the electrolyte permeability and ion transport capacity by introducing oxygen vacancies and lattice defects. In addition, the core–shell structure of nanorods combined with nanosheets increases the specific surface area of the material, enhances the structural stability of the material, provides more transmission channels for ions, and improves the electrochemical reaction rate and cycle stability of the material. In the three-electrode test system, the specific capacitance of La–Fe₂(MoO₄)₃@CoMoO₄ nanomaterials only slightly decreased from 1985 F g⁻¹ to 1963 F g⁻¹ after 10 000 charge–discharge cycles at a current density of 5 A g⁻¹, with a capacitance retention rate of 98.8%, demonstrating excellent cycle life. Moreover, the composite material of molybdenum dioxide (MoO₂) and carbon nanotubes (CNTs) combines the excellent conductivity and ion diffusion performance of both, providing strong support for efficient energy storage. The asymmetric supercapacitor composed of La–Fe₂(MoO₄)₃@CoMoO₄ and CNTs/MnO₂ anode exhibits excellent comprehensive performance, with an energy density as high as 50.2 Wh kg⁻¹ and a power density reaching 12 000 W kg⁻¹, providing an effective strategy for the design and development of high-performance supercapacitors.