Orthorhombic LiMnO2, cathodes suffer severe capacity fading due to accelerated manganese dissolution at elevated temperatures. Fluorine-modified LiMnO2 cathodes prepared by a solid-state reaction show less cation mixing and a well-defined crystallinity with a larger grain/powder morphology. The cathodes exhibit improved capacity retention and rate capability at the elevated temperature (55 degrees C) compared with undoped counterparts. (c) 2005 Elsevier B.V. All rights reserved.