Investigation of Temperature- and Frequency- Dependent Dielectric Study of LiNi0.3Co0.3Mn0.3O2 and LiNi0.3Co0.3Mn0.3Ba0.1O2 for Cathode Materials

LiNi0.3Co0.3Mn0.3O2 (NCM) and LiNi0.3Co0.3Mn0.3Ba0.1O2 (Ba-NCM) cathode materials were synthesized adopting a sol–gel synthetic protocol (using citric acid as a chelating agent). The crystalline nature of synthesized materials was evident from XRD analysis. Both samples were found to be almost perfectly matching with an α-NaFeO2 structure and indexed with the space group R3̅m. SEM results show a polygon shape with sharp edges, indicating their high crystallinity. The dielectric study at different temperatures (300–400 K) was done using electrical impedance spectroscopy. The Nyquist plots were fitted using ZView software. It was observed that multiple relaxation processes were involved, i.e., bulk and grain boundary effects. The conductivity graphs obey Jonscher's universal power law. Analysis of frequency-dependent ac conductivity shows that the small polaron hopping (SPH) mechanism is dominant for the NCM sample, whereas correlated barrier hoping (CBH) was dominant in Ba-NCM. The dielectric spectra of both samples showed a decrease in dielectric constant with an increase in the frequency of the applied field.