Mixed ternary metal MFeCo (M = Al, Mg, Cu, Zn, or Ni) oxide electrodes for high-performance energy storage devices

In this research, mixed ternary metal MFeCo (M = Al, Mg, Cu, Zn, or Ni) oxide electrodes were synthesized via a facile hydrothermal method without using any binding material. FE-SEM and TEM investigations showed that these electrodes were composed of various nano-structures (nano-sheets, nano-flake, and nano-wires) in different proportions and dimensions that could be controlled by altering synthesis temperature. Voltammetric measurements at 50 mV s(-1) revealed that NiFeCo and ZnFeCo oxides, both with a specific capacitance of 943 and 948 F g(-1), respectively, provided the highest capacitance with a significant difference from AlFeCo, MgFeCo, CuFeCo oxides, and FeCo2O4 which their specific capacitance values were 464, 313, 271, and 704 F g(-1), respectively. These electrodes showed great stability and 86% of their capacity was still available after 4000 cycles of charge and discharge. Galvanostatic charge-discharge experiments were carried out to obtain power and energy density of the electrodes confirming superior electrochemical activity of the zinc and nickel-supplemented electrodes with an energy density as high as 50 and 48 W h kg(-1), respectively. Eventually, according this study, mixed ternary metal oxides provide multiple oxidation states and could enhance the electrochemical performance of electrodes in charge storage applications.