US 20060035150A1
(19) United States
(12) Patent Application Publication (io) Pub. No.: US 2006/0035150 Al
Audemer et al. (43) Pub. Date: Feb. 16,2006
(54) CARBON-COATED LI-CONTAINING POWDERS AND PROCESS FOR PRODUCTION THEREOF
(76) Inventors: Albane Audemer, Lier (BE); Calin
Wurm, Amiens (FR); Mathieu
Morcrette, Amiens (FR); Sylvain
Gwizdala, Brienon sur Armancon (FR);
Christain Masquelier, Amiens (FR)
Correspondence Address:
HUTCHISON & MASON PLLC
PO BOX 31686
RALEIGH, NC 27612 (US)
(21) Appl. No.: 10/518,560
(22) PCT Filed: Jun. 19, 2003 (86) PCT No.: PCT/EP03/06628
Related U.S. Application Data
(60) Provisional application No. 60/392,978, filed on Jul. 2, 2002.
(30) Foreign Application Priority Data
Jun. 21, 2002 (EP) 02291562.3
The invention provides a new route for the synthesis of carbon-coated powders having the olivine or NASICON structure, which form promising classes of active products for the manufacture of rechargeable lithium batteries. Carbon-coating of the powder particles is necessary to achieve good performances because of the rather poor electronic conductivity of said structures. For the preparation of coated LiFeP04, sources of Li, Fe and phosphate are dissolved in an aqueous solution together with a polycarboxylic acid and a polyhydric alcohol. Upon water evaporation, polyesterification occurs while a mixed precipitate is formed containing Li, Fe and phosphate. The resin-encapsulated mixture is then heat treated at 700° C. in a reducing atmosphere. This results in the production of a fine powder consisting of an olivine LiFeP04 phase, coated with conductive carbon. When this powder is used as active material in a lithium insertion-type electrode, fast charge and discharge rates are obtained at room temperature and an excellent capacity retention is observed.
