High-temperature combustion synthesis and electrochemical characterization of LiNiO2, LiCoO2 and LiMn2O4 for lithium-ion secondary batteries

Lithium nickelate (Li0.88Ni1.12O2), lithium cobaltate (LiCoO2) and lithium manganate (LiMn2O4) were synthesized by fast self-propagating high-temperature combustion and their phase purity and composition were characterized by X-ray diffraction and inductively coupled plasma spectroscopy. The electrochemical behaviour of these oxides was investigated with regard to potential use as cathode materials in lithium-ion secondary batteries. The cyclic voltammograms of these cathode materials recorded in 1 M LiClO4 in propylene carbonate at scan rates of 0.1 and 0.01 mV s(-1) showed a single set of redox peaks Charge-discharge capacities of these materials were calculated from the cyclic voltammograms at different scan rates. The highest discharge capacity was observed in the case of Li0.88Ni1.12O2 In all the cases, at a very slow scan rate (0.01 mV s(-1)) the capacity of the charging (oxidation) process was higher than the discharging (reduction) process. A strong influence of current density on the charge-discharge capacity was observed during galvanostatic cycling of Li0.88Ni1.12O2 and LiMn2O4 cathode materials. LiMn2O4 can be used as cathode material even at higher current densities (1.0 mA cm(-2)), whereas in the case of Li0.88Ni1.12O2 a useful capacity was found only at lower current density (0.2 mA cm(-2)). For the fast estimation of the cycling behaviour of LiMn2O4, a screening method was used employing a simple technique for immobilizing microparticles on an electrode surface.