Ternary nanostructured MZnCo oxides (M=Al, Mg, Cu, Fe, Ni) prepared by hydrothermal method as excellent charge storage devices

Electrochemical properties of the spinel groups of MZnCo oxides (M=Al, Mg, Cu, Fe, Ni) as the active electrode materials are studied and compared in this investigation. Different morphologies (nano-sheets and nano-wires) of such transition metal oxides were hydrothermally synthesized at 150 degrees C for 5 h on a Ni foam as substrate. Their capacitive behavior is analyzed with cyclic voltammetry, chrono-potentiometry, and electrochemical impedance spectroscopy to compare their performance as the charge storage devices. The charge storage capacity of ZnCo2O4, AlZnCo, MgZnCo, CuZnCo, FeZnCo, and NiZnCo oxides was found to be 917, 995, 886, 702, 682, 462 C g(-1), respectively, at 50 mV s(-1) scan rate. Among them, the highest specific capacity was found to be for AlZnCo oxide (at below 50 mV s(-1) scan rates) and also for MgZnCo oxide (at higher 50 mV s(-1) scan rates). The obtained results represent that the specific capacity of CuZnCo, FeZnCo, and NiZnCo oxide electrodes is lower than ZnCo2O4 oxide in all the scan rates. The cyclic life of all the electrodes shows excellent life performance after 5000 cycles. According to the obtained results, MZnCo oxide with multiple oxidation states showed superior electrochemical properties for electrochemical applications as a result of the rapid ion/electron transfer.