Submicronic particles of manganese carbonate prepared in reverse micelles:: A new electrode material for lithium-ion batteries

A new preparation procedure based on the use of reverse micelles is used in the synthesis of manganese carbonate. A novel monodispersed form of MnCO3 is obtained, in which particles with a regular shape and ca. 200 nm edges are observed by electron microscopy. The thermal decomposition at 400 degrees C of this solid under argon leads to the formation of MnO submicron particles. As-prepared MnCO3 and the product of calcination, MnO, were tested in lithium cells. The electrochemical reaction with lithium of the new MnCO3 material takes place by a different conversion reaction than the corresponding oxide. The low molecular-weight of MnCO3 does not penalize the capacity while giving extra stability due to the formation of lithium carbonate as the main side product, which yields better capacity retention. In contrast to other anodes in recent commercial Li-ion product, the use of MnCO3 submicron particles avoids the presence of the more toxic and expensive cobalt in the stoichiometry of the active electrode material. (C) 2007 Elsevier B.V. All rights reserved.