Dear Rasu

In Nb2O5, like other semiconductors, the concentration of charge carriers is

directly related to the defect structure of the metal oxide which is dependent on

temperature and oxygen pressure. Greener et al. conducted a detailed analysis of  the relation between conductivity of α-Nb2O5 (monoclinic) and temperature under ambient oxygen pressure [1]. They showed that an increase in temperature and decrease in oxygen partial pressure increased the conductivity of α-Nb2O5. These results are in excellent agreement with the measurements by Kofstad and Chen et al. [2, 3]. 

 The structural changes of the Nb2O5 cathodes which are caused by discharging and recharging were investigated using Xray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and X-ray absorption fine structure (XAFS) analysis methods [4,5]. They suggested that tetragonal-Nb2O5 exhibited the best cycling performance with a large discharge capacity of 190 mAh g–1 for up to 30 cycles. XRD analysis suggested that the orthorhombic- and tetragonal-Nb2O5 maintain their original crystal lattices, accompanying a small change in the cell volume even after the Li+

intercalation. However, the two-dimensional layered structure of tetragonal-Nb2O5 was suggested to be the best for accommodating a large concentration of the intercalating ions [5].

[1] E. H. Greener, D. H. Whitmore, and M. E. Fine, "Electrical conductivity of

near‐stoichiometric α‐Nb2O5," The Journal of Chemical Physics, vol. 34, pp.

1017-1023, 1961.

[2] P. Kofstad, "Studies electrical conductivity of Nb2O5 as a function of oxygen

pressure at 600-1200 degrees C," Journal of Physics and Chemistry of Solids,

vol. 23, p. 1571, 1962.

[3] W. K. Chen and R. A. Swalin, "Studies on the defect structure of α-Nb2O5,"

Journal of Physics and Chemistry of Solids, vol. 27, pp. 57-64, 1966.

[4] N. Kumagai, K. Tanno, T. Nakajima, and N. Watanabe, "Structural-changes

of Nb2O5 and V2O5 as rechargeable cathodes for lithium battery,"

Electrochimica Acta, vol. 28, pp. 17-22, 1983.

[5] R. Kodama, Y. Terada, I. Nakai, S. Komaba, and N. Kumagai,

"Electrochemical and in situ XAFS-XRD investigation of Nb2O5 for

rechargeable lithium batteries," Journal of The Electrochemical Society, vol.

153, pp. A583-A588, 2006.

Dear Madam,

Thanks for your kindest very imperative information's.