NEGATIVE ELECTRODE MATERIAL FOR LI-ION BATTERIES

摘要

The invention relates to lithium cells, accumulators or batteries and more particularly to an active material for the negative electrode of rechargeable batteries. The invention more particularly relates to a material that comprises a phase of the general formula Li2 +v-4cCcTi3-wFexMyM'zO7-a, in which M and M' are metal ions of groups 2 to 15 with an ionic radius of between 0.5 and 0.8 Å in an oxygen octahedral environment, v, w, x, y, z and a being bonded by the relations 2a = -v+4w-3x-ny-n'z guaranteeing the electrical neutrality and n and n' being the respective formal oxidation degrees of M and M'; -0.5 = v = +0.5; y+z > 0; x+y+z = w and 0 < w = 0.3; characterised in that at least a portion of the lithium is substituted by carbon according to the relation 0 < c = (2+v)/4. The material has enhanced mass and volumetric capacities that can reach 190 Ah/kg while preserving the previously acquired advantages, including: a low capacity loss at the first cycle from 2 to 10 Ah/kg; excellent cyclability; and a low polarisation of 30 to 70 mV in C/15 mode.