| 摘要 |
Preparation of a carbon-bridged compound containing a transition metal, a fixed valency metal and lithium in the form of a phosphate, sulfate or silicate. Synthesis of compounds of formula CLi xM 1-yM 1> y(XO 4) n (A) comprises equilibrating in the required proportions an intimate and/or homogeneous mixture comprising: (a) a source of M in an oxidation state greater or less than that of the metal in the final compound; (b) a source of element M 1>; (c) a source of lithium; (d) optionally a source compound of X; and (e) a source of conductive carbon. C : bridged carbon to the compound CLi xM 1-yM 1> y(XO 4) n; x : 0-2; y : 0-0.6; n : 1-1.5; M : transition metal or mixture of the first series of the periodic table; M 1>Mg 2+>, Ca 2+>, Al 3+> or Zn 2+> or a combination of these; X : S, P or Si The sources M, M 1>, Li and X may be introduced in at least one stage and the synthesis takes place in thermodynamic or kinetic equilibrium in the desired proportions in a gaseous atmosphere so as to impose the oxidation state of the transition metal to the desired degree of valence; preferably this valence is 2 for Fe, Mn, Co, Ni and 3 or 4 for Ti and V. This is controlled by the composition of the gaseous atmosphere, the reaction temperature and the amount of the source (c) compound relative to (a), (b) and (d). The process includes a stage of pyrolysis of compound (e) to obtain a compound for which the electronic conductivity, measured on the compacted powder at a pressure greater or equal to 3000, preferably 3750 Kg.cm -2>, is greater than 10 -8> S.cm -1>. Independent claims are also included for the compounds (A) obtained and electrochemical cells containing the materials. |
