A series of spinel oxy-fluorides with the formula LiMn1.8Li0.1Ni0.1O4 F-- eta(eta) have been synthesized by both the conventional high-temperature (800 degrees C) firing method with LiF and a low temperature (450 degrees C) firing process with NH4HF2. Interestingly, the samples obtained by the high temperature (800 degrees C) procedure show no fluorine in the sample as revealed by the chemical analysis data, but an increase in lattice parameter and capacity values was observed due to a decrease in lithium content caused by the volatilization of LiF during the high temperature (800 degrees C) firing process. In contrast, the low-temperature fluorine doping approach was successful in incorporating fluorine into the spinel lattice, and the sample LiMn1.8Li0.1Ni0.1O3.85F0.15 exhibits a significant increase in discharge capacity compared to the oxide analog. (c) 2009 Elsevier B.V. All rights reserved.