LONG CYCLE LIFE LI-MN-O DEFECTIVE SPINEL ELECTRODES

A Li-Mn-O defective spinel phase material has been synthesized through repeated grinding and heating (T < 400 degrees C) steps from a mixtur e of LiOH and MnO2. The sample has been characterized by X-ray diffrac tion, thermogravimetric analysis and elemental and oxidation state ana lyses. At a C/12 charge/discharge rate, the material showed a first-cy cle capacity of almost 200 mAh/g that decreased upon cycling to a stab le value of 120 mA h/g after the 20th cycle. At a higher rate (C/3.7), the material showed a long cycle life upon Lithium insertion/deinsert ion with more than 50% of the initial capacity delivered at the 750th cycle. The work was developed within the ALPE (Advanced Lithium polyme r Electrolyte) battery project, an Italian project devoted to the real ization of lithium polymer batteries for electric vehicle applications . (C) 1998 Elsevier Science S.A. All rights reserved.