The structural and electrochemical properties of various Li-Al-Mn-O-F spinels were studied. Li[LixAlyMn2-x-y]O4-zFz (x=0, 0.05, 0, 0.1, 0 <= z <= 0.2) spinels were synthesized by a solid-state reaction method. Fluorine substitution in Li[LixAlyMn2-x-y]O4-zFz led to well-developed crystallization with octahedral morphology. In addition, Li[LixAlyMn2-x-y]O4-zFz showed superior cycling performance and better thermal stability than LiMn2O4 and LiAl0.1Mn1.9O4. Fluorine substitution also suppressed Mn dissolution which led to stable cycling performance at 55 degrees C. The differential scanning calorimetry (DSC) results showed that the anion (F for O) and cation (Li, Al for Mn) substituted spinel had better thermal stability than LiMn2O4, Li[AlyMn2-y]O-4, or Li[LixAlyMn2-x-y]O-4. (c) 2005 Elsevier B.V. All rights reserved.