Cathode materials of the Li1+xMn2O4-yFy family were successfully synthesized by a low-heating-temperature solid-state coordination method using lithium acetate, manganese acetate, lithium fluoride, citric acid, and polyethylene glycol (PEG) 400 as raw materials. X-ray diffractometry (XRD) proved that the Li1+xMn2O4-yFy powders were well-crystallized pure phase. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that the Li1+xMn2O4-yFy powders consisted of small and uniformly sized particles, with the diameter of the particles about 30-50 nm. Galvanostatic cycling results suggested that the Li1.05Mn2O3.95F0.05 gave an initial capacity of 128 mAh/g and had a retained capacity of 112 mAh/g at the 100th cycle within the potential range from 3.0 to 4.35 V and of 129 and 106 mAh/g between 3.0 and 4.8 V, respectively, which indicated that the sample possesses excellent electrochemical properties. The introduction of Li and F in LiMn2O4 apparently increases the capacity and significantly decreases the rate of capacity degradation during charge-discharge cycling. (C) 2007 The Electrochemical Society.