%0 Journal Article
%T Sn-x[BPO4](1-x) composites as negative electrodes for lithium ion cells: Comparison with amorphous SnB0.6P0.4O2.9 and effect of composition
%A Conte, D.E.
%A Aboulaich, A.
%A Robert, F.
%A Olivier-Fourcade, J.
%A Jumas, J.C.
%A Jordy, C.
%A Willmann, P.
%J Journal of Solid State Chemistry
%D 2010
%V 183
%N 1
%I ACADEMIC PRESS INC ELSEVIER SCIENCE
%@ 0022-4596
%F Conte_etal2010
%O ISI:000273834600010
%O exported from refbase (http://php.ecofog.gf/refbase/show.php?record=83), last updated on Wed, 04 May 2011 11:14:11 -0300
%X A comparative study of two Sn-based composite materials as negative electrode for Li-ion accumulators is presented. The former SnB0.6P0.4O2.9 obtained by in-situ dispersion of SnO in an oxide matrix is shown to be an amorphous tin composite oxide (ATCO). The latter Sn-0.72[BPO4](0.28) obtained by ex-situ dispersion of Sri in a borophosphate matrix consists of Sri particles embedded in a crystalline BPO4 matrix. The electrochemical responses of ATCO and Sn-0.72.[BPO4](0.28) composite in galvanostatic mode show reversible capacities of about 450 and 530 mAhg(-1), respectively, with different irreversible capacities (60% and 29%). Analysis of these composite materials by Sn-119 Mossbauer spectroscopy in transmission (TMS) and emission (CEMS) modes confirms that ATCO is an amorphous Sn-II composite oxide and shows that in the case of Sn-0.72[BPO4](0.28), the Surface of the tin clusters is mainly formed by Sn-II in an amorphous interface whereas the bulk of the clusters is mainly formed by Sn-0. The determination of the recoilless free fractions f (Lamb-Mossbauer factors) leads to the effective fraction of both Sn-0 and Sn-II species in such composites. The influence of chemical composition and especially of the surface-to-bulk tin species ratio oil the electrochemical behaviour has been analysed for several Sn-x[BPO4](1-x) composite materials (0.17 < x < 0.91). The cell using the compound Sn-0.72[BPO4](0.28) as active material exhibits interesting electrochemical performances (reversible capacity of 500 mAh g(-1) at C/5 rate). (C) 2009 Elsevier Inc. All rights reserved.
%K Sn-based composites
%K Lithium-ion batteries
%K Negative electrodes
%K Mossbauer spectroscopy
%K LixSn alloys
%P 65-75