The effect of cation ordering on the structure, electrical and electronic properties of cubic spinel LiNi0.5Mn1.5O4

Edi Yasa Ardiansyah; Mohd Sobri Idris; Rozana Aina Maulat Osman; Fahmi Fahmi

doi:10.58915/ijneam.v18i1.1708

Authors

Edi Yasa Ardiansyah Centre of Excellence for Frontier Materials Research, Universiti Malaysia Perlis, 02600 Arau, Perlis, Malaysia
Mohd Sobri Idris Dept. of Materials Engineering, Faculty of Chemical Engineering & Technology, Universiti Malaysia Perlis, 02600 Arau, Perlis, Malaysia
Rozana Aina Maulat Osman Dept. of Electronics Engineering, Faculty of Electronics Engineering & Technology, Universiti Malaysia Perlis, 02600 Arau, Perlis, Malaysia
Fahmi Fahmi Dept. of Electrical Engineering, Faculty of Engineering, Universitas Sumatera Utara, 20155 Medan, Indonesia.

DOI:

https://doi.org/10.58915/ijneam.v18i1.1708

Abstract

In this paper, we present the investigation of the impact of cation ordering on the structural, electrical, and electronic properties of a cubic spinel LiNi_0.5Mn_1.5O₄. Rietveld refinement using X-ray diffraction (XRD) data reveals that LiNi_0.5Mn_1.5O₄ annealed at 700 °C adopts a well-ordered atomic arrangement in cubic spinel (SG = P4₃32). Then, it is transformed to a disordered cubic spinel (SG = Fd-3m) at higher temperatures (> 800 °C). Impedance spectroscopy is employed to evaluate the dielectric and electrical properties in the temperature range of 0 to 25^oC within the frequency range between 10 Hz and 100 kHz. The Cole-Cole plot indicates that grain boundaries contribute significantly to electrical conductivity and that bulk resistance decreases with increasing temperature. The AC conductivity analysis shows that the electrical conductivity of well-ordered and disordered cubic spinel LiNi_0.5Mn_1.5O₄ exhibits thermal activation and obeys Jonscher's universal power law. Furthermore, the electronic properties of cubic spinel LiNi_0.5Mn_1.5O₄ with the space groups of Fd-3m and P4₃32 are investigated using the density functional theory (DFT) plane-wave method. The electronic analysis of the cubic spinel LiNi_0.5Mn_1.5O₄(SG = Fd-3m) indicates stronger bonding between oxygen and transition metal elements compared to the LiNi_0.5Mn_1.5O₄(SG = P4₃32) structure. Therefore, LiNi_0.5Mn_1.5O₄ with the Fd-3m space group exhibits high structural stability, making it a favourable cathode material for high-voltage rechargeable lithium-ion batteries.