Electrochemical characteristics of cobalt-substituted lithium nickel oxides synthesized from lithium hydro-oxide and nickel and cobalt oxides

LiNi1−yCoyO2 (y=0.1, 0.3 and 0.5) were synthesized by solid state reaction method at 800 °C and 850 °C from LiOH·H2O, NiO and Co3O4 as starting materials. The electrochemical properties of the synthesized LiNi1−yCoyO2 were investigated. As the content of Co decreases, particle size decreases rapidly and particle size distribution gets more homogeneous. When the particle size is compared at the same composition, the particles synthesized at 850 °C are larger than those synthesized at 800 °C. LiNi0.7Co0.3O2 synthesized at 850 °C has the largest intercalated and deintercalated Li quantity Δx among LiNi1−yCoyO2 (y=0.1, 0.3 and 0.5). LiNi0.7Co0.3O2 synthesized at 850 °C has the largest first discharge capacity (178 mAh/g), followed by LiNi0.7Co0.3O2 (162 mAh/g) synthesized at 800 °C. LiNi0.7Co0.3O2 synthesized at 800 °C has discharge capacities of 162 and 125 mAh/g at n=1 and n=5, respectively.