Studies of tin-transition metal-carbon and tin-cobalt-transition metal-carbon negative electrode materials prepared by mechanical attrition

Samples of Sn30TM30C40 and of Sn30Co15TM15C40. with TM = 3d transition metals, were prepared by vertical-axis attritor milling. The structure and performance of these samples were studied by X-ray diffraction (XRD) and by electrochemical testing. The XRD patterns of Sn30TM30C40 show an amorphous-like diffraction pattern only for the sample with TM = Co. The other prepared samples show broadened Bragg peaks of their main starting material, along with an amorphous-like background, even after 32 h of milling. Samples with TM = Co and TM = Ni show stable differential capacity versus potential plots and stable cycling for at least 100 cycles with reversible capacities of 425 and 250 mAh g(-1). respectively. All samples prepared with 15 at.% Co, show good capacity retention for at least 100 cycles ranging from 270 mAh g(-1) for samples with TM = Ni to 500 mAh g-1 for samples with TM = Ti. The differential capacity versus potential plots for all the prepared Sn30Co15TM15C40 samples show similar structure to that of Sn30Co30C40 except when TM = Cu. This shows the possibility of preparing tin-based negative electrode materials using a combination of cobalt and TM, especially if one looks to reduce the cobalt content. (C) 2009 Elsevier B.V. All rights reserved.