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.