Structural and electrical properties of nanostructured Ni0.25Co0.75MnP2O7

The nanostructured pyrophosphate Ni0.25Co0.75MnP2O7 was prepared. The synthesis technique was based on the hydrothermal method at 150 °C using poly-ethylene-glycol (PEG-10000) as surfactant with further calcination at 500 °C. A structural analysis of Ni0.25Co0.75MnP2O7 compound was carried out by applying X-ray diffraction (XRD) and using the Rietveld method. Morphological characterizations were performed using a scanning electron microscope (SEM) and transmission electron microscopy (TEM). A comparative study of the electrical conductivity of Mn2P2O7 and Ni0.25Co0.75MnP2O7 nanomaterials was carried out by impedance spectroscopy in the temperature range 500–680 °C. The activation energies for MnP2O7 and Ni0.25Co0.75MnP2O7 were 2.00 and 0.88 eV, respectively. Ni0.25Co0.75MnP2O7 nanomaterial presents a good electric conductivity compared to Mn2P2O7, due to the substitution effect. The improvement of the electronic and ionic conductivity makes the Ni0.25Co0.75MnP2O7 nanomaterial possible electrode materials for rechargeable batteries. The electrochemical behaviors of Ni0.25Co0.75MnP2O7 were studied using cyclic voltammetry.