XPS and ionic conductivity studies on Li2O-Al2O3-(TiO2 or GeO2)-P2O5 glass-ceramics

Chowdari, B. V. R. ; Subba Rao, G. V. ; Lee, G. Y. H. (2000) XPS and ionic conductivity studies on Li2O-Al2O3-(TiO2 or GeO2)-P2O5 glass-ceramics Solid State Ionics, 136-137 . pp. 1067-1075. ISSN 0167-2738

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Official URL: http://www.sciencedirect.com/science/article/pii/S...

Related URL: http://dx.doi.org/10.1016/S0167-2738(00)00500-2

Abstract

Lithium ion conducting glass-ceramics composed of the crystalline conducting phase LiM2(PO4)3 (M=Ti and Ge) in which the M4+ ions are partially substituted by Al3+ ions (Li-analogue of NASICON) have been synthesized by heat-treatment of Li2O-Al2O3-MO2-P2O5 (M=Ti and Ge) glasses. The as-prepared and annealed glasses and glass-ceramics have been characterized by XRD, DSC, XPS and conductivity techniques. The glass transition temperature, Tg of the annealed glasses was found to be 601°C and 474°C for the M=Ti and Ge glass systems whereas the crystallization temperature, Tc of the annealed glasses are 644°C and 578°C respectively. XPS studies show that the O 1s spectra for all the glasses and glass-ceramics could be deconvoluted into two peaks corresponding to the non-bridging (NBO) and bridging oxygen (BO) atoms. The binding energies (BE) of Li, Ti, Ge, Al and P have also been listed. In the Li2O-Al2O3-TiO2-P2O5 system, the deconvoluted Ti 2p XPS spectra indicate the existence of two oxidation states of titanium, 3+ and 4+. The Ti 2p and Ge 3d core levels are characterized by high BEs, suggesting that Ti4+-O and Ge4+-O bonds are highly ionic in character. The glass-ceramics show fast ion conduction (σ303 K=6.53×10−4 (M=Ti) and 3.99×10−4 S cm−1 (M=Ge)) and low Ea value (0.31 eV). These σ values are slightly higher than the corresponding crystalline Li1+xM2-xAlxP3O12 (M=Ti and Ge) phases and four to five orders of magnitude higher than the respective glassy phases. Plausible explanation for the enhancement of σ in glass-ceramics is given. It is suggested that the M=Ge glass-ceramics can be used as a solid electrolyte in the all-solid state Li-ion rechargeable battery.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Lithium Ion Conducting Glass-ceramics; Glass-ceramics; Ion Conduction
ID Code:52040
Deposited On:02 Aug 2011 08:20
Last Modified:02 Aug 2011 08:20

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