Synthesis and electrochemical characteristics of LiNi0.5Co0.5O2 from different combinations of carbonates and oxides

Cathode materials with a composition of LiNi0.5Co0.5O2 were synthesized by a solid-state reaction method at 850 °C using Li2CO3, NiO or NiCO3, and CoCO3 or Co3O4, as the sources of Li, Ni, and Co, respectively. Electrochemical properties, structure, and microstructure of the synthesized LiNi0.5Co0.5O2 samples were analyzed. The curves of voltage vs. x in LixNi0.5Co0.5O2 for the first charge–discharge and the intercalated and deintercalated Li quantity Δx were studied. The destruction of unstable 3b sites and phase transitions are discussed from the first and second charge–discharge curves of voltage vs. x in LixNi0.5Co0.5O2. The LiNi0.5Co0.5O2 sample synthesized from Li2CO3, NiO, and Co3O4 has the largest first discharge capacity (159 mAh/g), with a discharge capacity deterioration rate of 5.8 mAh/g/cycle.