In this paper structural, transport and electrochemical characterization of series of LiNi0.5-yCuyMn1.5O4 (y = 0, 0.02 and 0.05) cathode materials synthesized using sol-gel method are presented. We observed influence of annealing temperature on the lattice constant length, related to degree of oxygen nonstoichiometry. We found a correlation between activation energy of electrical conductivity and the lattice constant parameter. Among the analyzed materials the best electrical conductivity revealed LiNi0.48Cu0.02Mn1.5O4 annealed at 800 degrees C. Charge curves of the cells exhibited 4.7 V-plateau related to oxidation of Ni2+ to Ni4+ and 4 V region related to oxidation of Mn3+ to Mn4+. (C) 2014 Elsevier B.V. All rights reserved.