Li2MnO3-based composite cathodes for lithium batteries: A novel synthesis approach and new structures

A new, simple technique has been demonstrated for fabricating high-capacity composite electrode structures. In this technique, Li2MnO3 is leached in acid in the presence of soluble transition metal ions and subsequently annealed between 450 and 850 °C. The technique can be used to prepare a wide variety of composite compounds, in particular, a new family of ‘layered–rocksalt’ xLi2MnO3·(1−x)MO (e.g., M = Ni and Co) structures and modifications thereof, as well as ‘layered–layered’ xLi2MnO3·(1−x)LiMO2 (e.g., M = Mn, Ni, and Co) and ‘layered–spinel’ xLi2MnO3·(1−x)LiM2O4 (e.g., M = Mn and Ni). This novel approach also holds promise for 1) synthesizing materials that reduce the extent of internal phase transitions of composite cathode structures with a high manganese content, and 2) minimizing the extent to which cells need to be electrochemically activated to remove Li2O, thereby reducing the extent of the irreversible capacity loss on the first charge/discharge cycle.

► New, versatile technique used to synthesize high-capacity electrodes from Li2MnO3. ► New composite 'layered-rocksalt' materials identified. ► Technique holds promise for minimizing 1st-cycle capacity loss and phase transitions.