Non-equimolar high-entropy oxides with superior electrochemical performance: an example of (Mg-Co-Ni-Cu-Zn)O rock-salt oxides
摘要
In this study, a series of non-equimolar ratio high-entropy rock-salt-type oxides (Mg, Co, Ni, Cu, Zn)O were prepared a high-temperature solid-phase method with tailored cation ratios, and their physical phase compositions and electrochemical properties were investigated. The result shows that (Mg, Co, Ni, Cu, Zn)O with varying elemental ratios form single-phase rock-salt structures when they are sintered at 1100°C under non-equimolar conditions. These oxides display a uniformly elemental distribution and irregular spherical particle morphology. With the increase in Ni or Co content, the electrochemical performance is significantly improved. Compared to the other six high-entropy oxides, (Mg0.1625, Co0.1625, Ni0.35, Cu0.1625, Zn0.1625)O powders have demonstrated excellent energy storage properties and rate capability, achieving a specific capacitance of 384.3 F/g at 1 A/g and a coulombic efficiency of 88.9%. These results demonstrate that non-equimolar (Mg, Co, Ni, Cu, Zn)O high-entropy rock-salt-type oxides have promising potential as advanced electrode materials.
Graphical Abstract