Improving the cycle stability of LiCoPO{sub 4} nanocomposites as 4.8 V cathode: Stepwise or synchronous surface coating and Mn substitution

Journal Article · Wed Jun 15 00:00:00 EDT 2016 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2016.04.009· OSTI ID:22587158

Örnek, Ahmet ^[1]; Can, Mustafa ^[2]; Yeşildağ, Ali ^[3]

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1. Kafkas University, Atatürk Vocational School of Health Science, Kars (Turkey)
2. Sakarya University, Arifiye Vocational School, Sakarya (Turkey)
3. Kafkas University, Faculty of Engineering and Architecture, Department of Bioengineering, Kars (Turkey)

Nanostructured LiCo{sub 1−x}Mn{sub x}PO{sub 4}/C (x = 0 and 0.05) materials were successfully produced as superior quality cathodes by combined sol-gel and carbothermal reduction methods. X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), energy dispersive spectroscopy (EDS), fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma (ICP), cyclic voltammetry (CV) and galvanostatic measurements were applied to determine the phase purity, morphology and electrochemical qualifications. HR-TEM analysis reveals that the thickness of the surface carbon layer of 5 to 10 nm range with the uniform distribution. LiCo{sub 0·95}Mn{sub 0·05}PO{sub 4}/C particles were between 40 and 80 nm and the same material exhibits a higher and stable reversible capacity (140 mA h g{sup −1}) with the long voltage plateau (4.76 V). Substitution of Co{sup 2+} with Mn{sup 2+} in LiCoPO{sub 4}/C has an influence on the initial discharge capacity and excellent cycling behaviour. The obtained results have attributed that production dynamics in nano-synthesis, the coating process with proper carbon source and an effective doping represent three parameters to prepare favorable cathode materials. - Highlights: • Structural, morphological and electrochemical effects of Mn doped LiCo{sub 1−x}Mn{sub x}PO{sub 4}–C electrodes are investigated. • Cheap, effective and simple sol-gel assisted carbothermal reduction approach is used. • After 60th cycle, capacity retention is almost 92% for LiCo{sub 0·95}Mn{sub 0.05}PO{sub 4}–C electrode. • Mn-doped sample exhibits distinctive oxidation (4.76 V and 4.12 V) peaks.

• OSTI ID: 22587158
• Journal Information: Materials Characterization, Vol. 116; Other Information: Copyright (c) 2016 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

36 MATERIALS SCIENCE
77 NANOSCIENCE AND NANOTECHNOLOGY
CATHODES
COBALT PHOSPHATES
DOPED MATERIALS
ELECTROCHEMISTRY
ELECTRON SCANNING
FIELD EMISSION
FOURIER TRANSFORM SPECTROMETERS
FOURIER TRANSFORMATION
INFRARED SPECTRA
NANOCOMPOSITES
NANOSTRUCTURES
SCANNING ELECTRON MICROSCOPY
SOL-GEL PROCESS
SURFACE COATING
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
X-RAY PHOTOELECTRON SPECTROSCOPY