Investigation of Temperature- and Frequency- Dependent Dielectric Study of LiNi_0.3Co_0.3Mn_0.3O₂ and LiNi_0.3Co_0.3Mn_0.3Ba_0.1O₂ for Cathode Materials

Abstract

LiNi 0.3 Co 0.3 Mn 0.3 O 2 (NCM) and LiNi 0.3 Co 0.3 Mn 0.3 Ba 0.1 O 2 (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-NaFeO 2 structure and indexed with the space group R3̅ m. 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.

Inhibition of Oxygen Vacancy Derived from Donor Doping in Relaxor Ferroelectric Films for Improving Dielectric Energy Storage

“…Relaxor ferroelectric capacitors have received extensive attention for energy storage due to their low energy loss and high recovery energy efficiency . However, they suffer from the comparatively low energy storage density due to the adverse coupling between the breakdown electric field and the polarization since both the high maximum polarization P max and breakdown field strength E BDS are necessary for high energy storage density. − Therefore, how to improve E BDS and P max simultaneously to obtain excellent energy storage characteristics has become the recent focus …”