<abstract xmlns="http://www.w3.org/1999/xhtml">Layered oxide LiMO2 (Ni, Co, Mn) have been proposed as cathode materials for lithium-ion batteries. Mainly LiNiO2 is accepted as an attractive cathode material because of its various advantages such as low cost, high discharge capacity, good reversibility. The LiNi0.5Mn0.5O2 powders are synthesized by a sol-gel method using citric acid as a chelating agent. The structure of the synthesized material is analyzed by using XRD, FT-IR and the microstructures of the samples are observed by using FESEM. The intensities and positions of the peaks are in a good agreement with the previous results. The morphological changes are clearly observed as a result of manganese substitution. The Fourier transform infrared (FT-IR) spectra obtained with KBr pellet data reveal the structure of the oxide lattice constituted by LiO6 and NiO6 octahedra. The conductivity studies are characterized by (EIS) in the frequency range of 42 Hz to 1 MHz at room temperature to 120 °C. The dielectric properties are analyzed in the framework of complex dielectric permittivity and complex electric modulus formalisms. It indicates that the conductivity increases with increasing temperature. The fitting data of EIS plots replicate the non-Debye relaxation process with negative temperature coefficient of resistance (NTCR) behavior.</abstract>

Layered oxide LiMO2 (Ni, Co, Mn) have been proposed as cathode materials for lithium-ion batteries. Mainly LiNiO2 is accepted as an attractive cathode material because of its various advantages such as low cost, high discharge capacity, good reversibility. The LiNi0.5Mn0.5O2 powders are synthesized by a sol-gel method using citric acid as a chelating agent. The structure of the synthesized material is analyzed by using XRD, FT-IR and the microstructures of the samples are observed by using FESEM. The intensities and positions of the peaks are in a good agreement with the previous results. The morphological changes are clearly observed as a result of manganese substitution. The Fourier transform infrared (FT-IR) spectra obtained with KBr pellet data reveal the structure of the oxide lattice constituted by LiO6 and NiO6 octahedra. The conductivity studies are characterized by (EIS) in the frequency range of 42 Hz to 1 MHz at room temperature to 120 °C. The dielectric properties are analyzed in the framework of complex dielectric permittivity and complex electric modulus formalisms. It indicates that the conductivity increases with increasing temperature. The fitting data of EIS plots replicate the non-Debye relaxation process with negative temperature coefficient of resistance (NTCR) behavior.

Structural and conductivity studies of LiNi0.5Mn0.5O2 cathode materials for lithium-ion batteries

Advanced Analytical Laboratory, Andhra University, Visakhapatnam-530003, India

Department of Physics, Andhra University, Visakhapatnam-530003, India

Materials Science-Poland

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Structural and conductivity studies of LiNiMnO cathode materials for lithium-ion batteries

Layered oxide LiMO2 (Ni, Co, Mn) have been proposed as cathode materials for lithium-ion batteries. Mainly LiNiO2 is accepted as an attractive cathode material...

Temperature [°C]	AC conductivity [S/cm]
Temperature [°C]	LiNi_0.5Mn_0.5O₂
30	2.54×10⁻⁰⁷
40	4.24×10⁻⁰⁷
50	6.87×10⁻⁰⁷
60	1.03×10⁻⁰⁶
70	1.47×10⁻⁰⁶
80	1.78×10⁻⁰⁶
90	3.84×10⁻⁰⁶
100	4.75 × 10⁻⁰⁶
110	6.54 × 10⁻⁰⁶
120	3.52 × 10⁻⁰⁶

Source	Wavenumbers [cm⁻¹]
authors	421.4644	477.4024	512.0154	615.248
[37]	–	474	532	597

Compound	a [Å]	c [Å]	c/a	Cell volume [Å]³	I₀₀₃/I₁₀₄	R-factor ((I₀₀₆+I₁₀₂)/I₁₀₁)	Crystallite size [nm]
LiNi_0.5Mn_0.5O₂	2.8798	14.3406	4.9797	102.9982	1.4891	0.20598	1.9526
LiNi_0.5Mn_0.5O₂[25, 26]	2.887	14.262	4.94	118.87	–	–	–

Structural and conductivity studies of LiNi_0.5Mn_0.5O₂ cathode materials for lithium-ion batteries

Article Category: Research Article

Published Online: Jun 18, 2016

Page range: 404 - 411

Received: Nov 12, 2015

Accepted: Jan 24, 2016

DOI: https://doi.org/10.1515/msp-2016-0038

Keywords
layered structure, FESEM, impedance, electric modulus

© Wroclaw University of Technology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Fig. 7

Fig. 8

Fig. 9

AC conductivity values of LiNi0.5Mn0.5O2 sample.

FT-IR wavenumbers variation of LiNi0.5Mn0.5O2 sample.

Lattice parameter, unit cell volume, I003/I104 and R-factor of LiNi0.5Mn0.5O2 sample.

Structural and conductivity studies of LiNi0.5Mn0.5O2 cathode materials for lithium-ion batteries

Article Category: Research Article

Published Online: Jun 18, 2016

Page range: 404 - 411

Received: Nov 12, 2015

Accepted: Jan 24, 2016

DOI: https://doi.org/10.1515/msp-2016-0038

Keywordslayered structure, FESEM, impedance, electric modulus

© Wroclaw University of Technology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Fig. 7

Fig. 8

Fig. 9

AC conductivity values of LiNi0.5Mn0.5O2 sample.

FT-IR wavenumbers variation of LiNi0.5Mn0.5O2 sample.

Lattice parameter, unit cell volume, I003/I104 and R-factor of LiNi0.5Mn0.5O2 sample.

Structural and conductivity studies of LiNi_0.5Mn_0.5O₂ cathode materials for lithium-ion batteries

Keywords
layered structure, FESEM, impedance, electric modulus