SOFT-CHEMISTRY SYNTHESIS OF ELECTROCHEMICALLY-ACTIVE SPINEL LIMN2O4 FOR LI-ION BATTERIES

Battery grade spinel-LiMn2O4 cathode-active material has been synthesi zed through a soft-chemistry aided low temperature precursor process. It has been found that the bulk quantities of submicron-sized spinel-L iMn2O4 powders can be obtained at a modest temperature as low as 300 d egrees C, with the highest level of phase purity without any residual impurities. This technique describes a simple solution mixing procedur e in the presence of a complexing agent, preferably a carboxylic acid, namely succinic acid. The details of the synthesis procedure are pres ented and the physical properties of the synthesized spinel are discus sed in the light of structural (XRD), spectroscopic (IR and Raman), an d thermal (DTA/TG) techniques. The electrochemical test cells (coin-ty pe) containing the synthesized spinel oxide as positive electrode in c onjunction with either lithium metal or carbonaceous (graphite) anode employing a nonaqueous organic electrolyte mixture of 1 M LiPF6 in EC + DMC + MF show an improved performance in terms of its capacity and c yclability over extended cycles. (C) 1998 Elsevier Science B.V. All ri ghts reserved.