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) andLiNi(0.3)Co(0.3)Mn(0.3)Ba(0.1)O(2) (Ba-NCM) cathode materials were synthesizedadopting a sol-gel synthetic protocol (using citric acid asa chelating agent). The crystalline nature of synthesized materialswas evident from XRD analysis. Both samples were found to be almostperfectly matching with an & alpha;-NaFeO2 structure andindexed with the space group R3 m. SEM results show a polygon shape with sharp edges, indicating theirhigh 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 observedthat multiple relaxation processes were involved, i.e., bulk and grain boundary effects. The conductivity graphs obey Jonscher'suniversal power law. Analysis of frequency-dependent ac conductivityshows that the small polaron hopping (SPH) mechanism is dominant forthe NCM sample, whereas correlated barrier hoping (CBH) was dominantin Ba-NCM. The dielectric spectra of both samples showed a decreasein dielectric constant with an increase in the frequency of the appliedfield.