In this present work, we have discussed about the synthesis of LiNi0.5Mn1.5O4 by microwave-assisted sol–gel method using glycine as a chelating agent. The structural, morphological and chemical compositions of the synthesized material are confirmed using XRD, SEM with EDX and ICP, respectively. Dielectric measurements are analyzed in the frequency range of 50 Hz to 5 MHz under the temperature between 308 and 783 K. Nyquist plot observed the non-Debye type-behavior and analyzed the individual contribution of grain, grain boundary and interfacial effect in the material. Activation energy from the Arrhenius plot and the relaxation time from the impedance spectroscopy have been analyzed. Conductivity shows the two distinct dispersion regions analyzed with jump relaxation model. Graphical Abstract: [Figure not available: see fulltext.] © 2016, Springer Science+Business Media New York.