The electrochemical performance of a Li-ion battery made from nanometric, highly crystalline LiNi0.5Mn1.5O4 as positive electrode and mesoporous carbon microbeads (MCMBS) as negative electrode was assessed. The best performance was obtained by using a slight excess of spinet (a cathode/anode mole ratio of 1.3) and lithium bis-oxalate borate (LiBOB) instead of LiPF6 as an electrolyte salt. Higher spinet contents caused the formation of metallic Li in the carbon and the rapid degradation of battery performance as a result. The calculated output energy was 322 Wh kg(-1) which is higher than the value reported for the LiMn2O4/C cell (250Wh kg(-1)). (C) 2008 Elsevier B.V. All rights reserved.