Synthesis of LiMn2O4 by modified Pechini method and characterization as a cathode for rechargeable Li/LiMn2O4 cells

Abstract

The Pechini process to produce LiMn2O4 powder is modified such that precursors are pre-ignited in open air followed by calcining in the range of 600 degrees C-800 degrees C for 4 h. The molar ratio (R) of ethylene glycol (EG) to citric acid (CA) is 0, 1, 2 or 4. The effect of EG content on powder characteristics and electrochemical performance is evaluated. With increasing R, the homogeneity and the specific surface area of the powder are increased. Lithium is evaporated during ignition (and/or the charring reaction) and calcination because of the inhomogeneous mixing and exothermic heat of decomposition of polymer. Samples calcined at 800 degrees C for 4 h yield maximum specific capacity for both charge and discharge (130.7 and 126.7 mA h g(-1)). The cycleability of the powder increases with increasing R. The effect of the EG content on the homogeneity is discussed. (C) 2000 Elsevier Science S.A. All rights reserved.