Dielectric and conduction mechanism studies of Ni doped LiMn2O4 synthesized by solution combustion method

In the present work, structural, morphological, dielectrical, and electrochemical properties of LiNixMn(2-x)O4 (where x=0, 0.1,0.3, 0.5mol%) prepared by solution combustion method were reported. X-ray diffraction studies confirmed the formation of cubic spinel structure without any impurity phases. Scanning electron micrographs revealed grains of micrometer range with a spherical like morphology and narrow size distribution. Dielectric parameters such as dielectric constant, dielectric loss, impedance, and electrical modulus were found to depend on temperature, frequency, and dopant concentration. AC conductivity was found to increase with increase in temperature exhibiting negative temperature co-efficient of resistance (NTCR) property in the material. Complex impedance and electrical modulus studies revealed the existence of temperature-dependent electrical relaxation in the material. The Correlated Barrier Hopping (CBH) model of conduction mechanism was confirmed by the decrease in s parameter with increase in temperature. Charge-discharge studies revealed the stabilization of spinel lattice by Ni ions, contributing to better capacity retention.