SYNTHESIS AND PROPERTIES OF LINIO2 AS CATHODE MATERIAL FOR SECONDARY BATTERIES

The optimum preparation condition and electrochemical properties of LiNiO2, as the cathode material for lithium secondary batteries were investigated. LiNiO2 samples were prepared from Li(OH)(2) . H2O and Ni(OH)(2) in the range from 500 to 900 degrees C. The compound prepared in an oxygen atmosphere at 700 degrees C exhibited the highest discharge capacity of 200 mAh/g in the voltage range from 3.0 to 4.3 V. The structure and charge-transfer resistance of the Li1-xNiO2 compound were examined at each state-of-charge by X-ray diffractometry and a.c. impedance spectroscopy. The charge-transfer resistances were low in the range of 0.15 <x<0.75, which was related to the expansion of the interlayer distance between NiO2 layers.