Effect of Mn substitution on the microstructure of (MgCoNiZnCu)O powder and its electrochemical performance as an anode material

High-entropy ceramic oxide powders, identified as (MgCoNiCuZn_0.2−xMn_x)O, were synthesized utilizing a hydrothermal technique. A variety of analytical methods, namely X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM‒EDS), and an electrochemical workstation, were applied to explore the impact of varying Mn substitution levels on the material’s characteristics. Findings indicate that variations in Mn substitution do not interfere with the emergence of a unique crystalline high-entropy carbonate solid solution, termed (MgNiCoZnCuMn)CO₃ (HECO₃Mns) phase. After undergoing high-temperature calcination, a multiphase material, characterized as (MgCoNiCuZn_0.2−xMn_x)O/MnCo₂O₄, is observed. This composite, integrating the merits of high-entropy oxide with those of a MnCo₂O₄ individual electrode, demonstrates superior electrode cycle stability and a notable augmentation in electrode capacity, contributing to a substantial enhancement in electrochemical attributes. When subjected to a current density of 0.1 A/g, the discharge capacity escalates from 465.8 to 945.6 F/g, with a capacity retention rate of 93% being maintained after 500 cycles.