Centre National De La Recherche Scientifique

Batscap

Blue Solutions

Benoit Morel

Marc Deschamps

Dominique Guyomard

Matthieu Dubarry

Joël Gaubicher

The invention relates to a lithium vanadium oxide which corresponds to the formula LiVO(0.1&#x2266;&#x3b1;&#x2266;0.25). It is composed of agglomerates of small needles having a length l from 400 to 1000 nm, a width w such that 10&#x3c;l/w&#x3c;100 and a thickness t such that 10&#x3c;l/t&#x3c;100. It is obtained by a process consisting in preparing a precursor gel by bringing &#x3b1;-VOand a Li precursor into contact in amounts such that the ratio of the concentrations [VO]/[Li] is between 1.15 and 1.5 and in subjecting the gel to a heat treatment comprising a first stage at 80&#xb0; C.-150&#xb0; C. for 3 h to 15 days and a second stage between 250&#xb0; C. and 350&#xb0; C. for 4 min to 1 hour, under a nitrogen or argon atmosphere. It is useful as an active material of a positive electrode.

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The invention relates to the preparation of an optionally carbonaceous &#x3b3;-LiVOmaterial. The process consists in preparing a composition formed of carbon and of precursors of Li and of V and in subjecting it to a heat treatment. The composition is prepared by bringing carbon, &#x3b1;-VOand a Li precursor into contact in amounts such that the ratio of the [VO]/[Li] concentrations is between 0.95 and 1.05 and the carbon is in excess of at least 25% with respect to the stoichiometry. The heat treatment is carried out in two stages: a first stage at a temperature between 90&#xb0; C. and 150&#xb0; C. for a time of 1 to 12 hours and a second stage at a temperature between 420&#xb0; C. and 500&#xb0; C. for a time of between 10 min and 1 hour, under a nitrogen or argon atmosphere or under vacuum. Applications: positive electrode active material.

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Champagne Mouton, France

Benoit Morel