TY  - JOUR
AU  - Conte, D.E.
AU  - Aboulaich, A.
AU  - Robert, F.
AU  - Olivier-Fourcade, J.
AU  - Jumas, J.C.
AU  - Jordy, C.
AU  - Willmann, P.
PY  - 2010//
TI  - Sn-x[BPO4](1-x) composites as negative electrodes for lithium ion cells: Comparison with amorphous SnB0.6P0.4O2.9 and effect of composition
T2  - J. Solid State Chem.
JO  - Journal of Solid State Chemistry
SP  - 65
EP  - 75
VL  - 183
IS  - 1
PB  - ACADEMIC PRESS INC ELSEVIER SCIENCE
KW  - Sn-based composites
KW  - Lithium-ion batteries
KW  - Negative electrodes
KW  - Mossbauer spectroscopy
KW  - LixSn alloys
N2  - 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.
SN  - 0022-4596
N1  - ISI:000273834600010
ID  - Conte_etal2010
ER  -