Preparation of high density LiNi0.8Co0.2O2 as cathode material for lithium ion battery by molten salt method

Eutectic mixture of LiOH-LiNO3 was studied with thermal analysis method. The cooling curve and t-x phase diagram of the eutectic mixture were plotted. The results show that the binary system is the simple binary eutectic systems and the lowest melt point of the eutectic mixture is 175.7°C. LiNi0.8Co0.2O2 for lithium ion battery was prepared by using molten salt LiOH-LiNO3 with high density precursor Ni0.8Co0.2(OH)2 at 600°C for 6 h and 800°C for 24 h, and the tap density of the prepared non-spherical LiNi0.8Co0.2O2 powder reached 3.23 g/cm3. XRD results show the material LiNi0.8Co0.2O2 has order NaFeO2 layer structure. Electrochemical property tests testify that for charge-discharge current density of 0.5 mA/cm2 and voltage of 3.0-4.3 V, the initial charge specific capacity of prepared LiNi0.8Co0.2O2 is 175 (mA·h)/g, and coulomb efficiency is 93%. The discharge specific capacity is 163 (mA·h)/g. The cathode material LiNi0.8Co0.2O2 with good electrochemical property can be prepared by this technology.