2004 Cells

200413.fm Page 20 Friday, February 27, 2004 9:14 AM

CellsF 3000 One-Step Low-Temperature Route for the Preparation of Electrochemically

Active LiMnPO4 Powders. — Pure and well-crystallized powders of the title com-pound are synthesized by a direct precipitation route in aqueous solutions of Mn(NO3)2, H3PO4, LiNO3, and LiOH at 373 K under well-defined pH conditions first predicted by thermodynamic calculations. The smallest precipitated particles (about 100 nm) lead to a global improvement of the electrochemical behavior when used a positive electrode in lithium batteries, consisting in lowering the polarization and enhancement of the re-versible capacities (approximately 70 mAh/g at C/20). The potential intermittent titra-tion technique and in situ XRD reveal a two-phase Li extraction/insertion mechanism between LiMnPO4 and the delithiated phase MnPO4 (space group Pmnb). — (DELACOURT, C.; POIZOT, P.; MORCRETTE, M.; TARASCON, J.-M.; MASQUELIER*, C.; Chem. Mater. 16 (2004) 1, 93-99; Lab. React. Chim. Solides, CNRS, Univ. Picardie Jules Verne, F-80039 Amiens, Fr.; Eng.) — W. Pewestorf

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