Structural, transport and electrochemical properties of LiNi_(0.5 ? y)Cu_yMn_(1.5)O_(4 ? δ) spinel cathode materials☆

摘要

In this paper structural, transport and electrochemical characterization of series of LiNi_(0.5-y)Cu_yMn_(1.5)O_4 (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 LiNi_(0.48)Cu_(0.02)Mn_(1.5)O_4 annealed at 800 ℃. Charge curves of the cells exhibited 4.7 V-plateau related to oxidation of Ni~(2+) to Ni~(4+) and 4 V region related to oxidation of Mn~(3+) to Mn~(4+).