Production of electrolytic manganese dioxide for usage in lithium batteries.

The epsilon phase of electrolytic manganese dioxide (END) is the structural form most easily converted in the LiMn2O4 spinel used as cathode in lithium batteries. Thus, employing titanium as anode, a study of electrolysis parameters was carried out in order to determine the best conditions to produce an epsilon-EMD suitable for that spinel preparation, The influence of solution temperature (65 degrees C and 90 degrees C) and current density (between 1 mA/cm(2) and 17.5 mA/cm(2)) on the anode potential and the EMD properties was investigated using an aqueous 2.0 mol/L MnSO4 + 0.30 mol/L H2SO4 solution, In any of the electrolysis conditions tested only the epsilon-EMD structure was obtained, but its specific surface area varied with the applied current density and temperature. Drying the epsilon-EMD at temperatures between 60 degrees C and 120 degrees C did not cause any phase changes, To produce a suitable EMD at the highest current density possible without passivation of the titanium anode, the best electrolysis parameters were determined to be 90 degrees C and 15 mA/cm2. The e-EMD thus obtained had a specific surface area (BET) of ca. 65 m(2)/g.