Electrochemical characteristics of partially cobalt-substituted LiMn2-yCoyO4 spinels synthesized by Pechini process

Un-substituted LixMn2O4 with various Li/Mn ratios and Co-substituted LiMn2-yCoyO4 spinels were prepared by the Pechini method. The precursors were calcined at 200degreesC for 6 h followed by heat-treatment at 800degreesC for 8 h. Crystalline structure and electrochemical characterization of the synthesized cathode materials for lithium batteries had been studied. The Co-substituted spinels showed an improvement on the cycling properties over the un-substituted one. Among the Co-substituted spinels, LiMn1.8Co0.2O4 exhibited the most promising cycling performance with initial specific discharge capacity of 110 mAh g(-1) and fading rate of 0.5 mAh g(-1) per cycle (or 0.45% per cycle). The improvement in cycling performance might be contributed by the stabilization of the spinel structure by smaller lattice constant when manganese ion was partially substituted by Co3+ ion. (C) 2002 Elsevier Science B.V. All rights reserved.