High-temperature combustion synthesis and electrochemical characterizationof 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-temperat ure combustion and their phase purity and composition were characterized by X-ray diffraction and inductively coupled plasma spectroscopy. The electro chemical behaviour of these oxides was investigated with regard to potentia l use as cathode materials in lithium-ion secondary batteries. The cyclic v oltammograms 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 re dox peaks Charge-discharge capacities of these materials were calculated fr om 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 inf luence of current density on the charge-discharge capacity was observed dur ing 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 estimatio n of the cycling behaviour of LiMn2O4, a screening method was used employin g a simple technique for immobilizing microparticles on an electrode surfac e.