Growth mechanism and magnetic and electrochemical properties of Na{sub 0.44}MnO{sub 2} nanorods as cathode material for Na-ion batteries

Journal Article · Wed Jul 15 00:00:00 EDT 2015 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2015.05.005· OSTI ID:22476115

Demirel, S.; Oz, E. ^[1]; Altin, E. ^[2]; Altin, S.; Bayri, A. ^[1]; Kaya, P.; Turan, S. ^[3]

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1. Physic Department, Inonu University, Malatya 44120 (Turkey)
2. Scientific and Technological Research Center, Inonu University, 44120 (Turkey)
3. Department of Materials Science and Engineering, Anadolu University, Eskisehir (Turkey)

Nanorods of Na{sub 0.44}MnO{sub 2} are a promising cathode material for Na-ion batteries due to their large surface area and single crystalline structure. We report the growth mechanism of Na{sub 0.44}MnO{sub 2} nanorods via solid state synthesis and their physical properties. The structure and the morphology of the Na{sub 0.44}MnO{sub 2} nanorods are investigated by X-ray diffraction (XRD), scanning and tunneling electron microscopy (SEM and TEM), and energy-dispersive X-ray (EDX) techniques. The growth mechanism of the rods is investigated and the effects of vapor pressure and partial melting of Na-rich regions are discussed. The magnetic measurements show an antiferromagnetic phase transition at 25 K and the μ{sub eff} is determined as 3.41 and 3.24 μ{sub B} from the χ–T curve and theoretical calculation, respectively. The electronic configuration and spin state of Mn{sup 3+} and Mn{sup 4+} are discussed in detail. The electrochemical properties of the cell fabricated using the nanorods are investigated and the peaks in the voltammogram are attributed to the diffusion of Na ions from different sites. Na intercalation process is explained by one and two Margules and van Laar models. - Highlights: • We synthesized Na{sub 0.44}MnO{sub 2} nanorods via a simple solid state reaction technique. • Our studies show that excess Na plays a crucial role in the nanorod formation. • Magnetization measurements show that Mn{sup 3+} ions are in LS and HS states. • The electrochemical properties of the cell fabricated using the nanorods are investigated. • Na intercalation process is explained by one and two Margules and van Laar models.

• OSTI ID: 22476115
• Journal Information: Materials Characterization, Vol. 105; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
ANTIFERROMAGNETISM
CATHODES
DIFFUSION
ELECTRIC BATTERIES
ELECTROCHEMISTRY
ELECTRONIC STRUCTURE
MAGNETIZATION
MANGANATES
MONOCRYSTALS
NANOSTRUCTURES
SCANNING ELECTRON MICROSCOPY
SODIUM COMPOUNDS
SOLIDS
SURFACE AREA
SYNTHESIS
TRANSMISSION ELECTRON MICROSCOPY
TUNNEL EFFECT
X-RAY DIFFRACTION