Das, B. ; Reddy, M. V. ; Malar, P. ; Osipowicz, Thomas ; Subba Rao, G. V. ; Chowdari, B. V. R. (2009) Nanoflake CoN as a high capacity anode for Li-ion batteries Solid State Ionics, 180 (17-19). pp. 1061-1068. 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/j.ssi.2009.05.007
Abstract
CoN films with nanoflake morphology are prepared by RF magnetron sputtering on Cu and oxidized Si substrates and characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM) and selected area electron diffraction (SAED) techniques. The thickness and composition of the films are determined by the Rutherford back scattering (RBS) technique confirming the stoichiometric composition of CoN with a thickness, 200 (± 10) nm. Li-storage and cycling behavior of nanoflake CoN have been evaluated by galvanostatic discharge-charge cycling and cyclic voltammetry (CV) in cells with Li-metal as counter electrode in the range of 0.005-3.0 V at ambient temperature. Results show that a first-cycle reversible capacity of 760 (± 10) mAhg−1 at a current rate 250 mAg−1(0.33 C) increases consistently to yield a capacity of 990 (± 10) mAhg−1 after 80 cycles. The latter value corresponds to 2.7 mol of cyclable Li/mol of CoN vs. the theoretical, 3.0 mol of Li. Very good rate capability is shown when cycled at 0.59 C (up to 80 cycles) and at 6.6 C (up to 50 cycles). The coloumbic efficiency is found to be 96-98% in the range of 10-80 cycles. The average charge and discharge potentials are 0.7 and 0.2 V, respectively for the decomposition/formation of Li3N as determined by CV. However, cycling to an upper cut-off voltage of 3.0 V is essential for the completion of the "conversion reaction". Based on the ex-situ-XRD, -HR-TEM and -SAED data, the plausible Li-cycling mechanism is discussed. The results show that nanoflake CoN film is a prospective anode material for Li-ion batteries.
Item Type: | Article |
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Source: | Copyright of this article belongs to Elsevier Science. |
Keywords: | CoN; Thin Films; Electrochemical Behavior; Anodes; Li-ion Batteries |
ID Code: | 52050 |
Deposited On: | 02 Aug 2011 08:25 |
Last Modified: | 02 Aug 2011 08:25 |
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