Structural, transport and electrochemical properties of LiNi0.5 − yCuyMn1.5O4 − δ spinel cathode materials

• Structural and transport properties of LiNi0.5 − yCuyMn1.5O4 − δ
• Best electrical properties for LiNi0.48Cu0.02Mn1.5O4 − δ
• Lattice parameter increases when the temperature of sintering increases.
• Oxygen nonstoichiometry increases when the temperature of sintering increases.
• Small Cu doping has a beneficial effect on the electrical conductivity.

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 °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 +.