Structural and Electrochemical Properties of LiNi1/3Mn1/3Co1/3O2 Cathode Material upon Aging in Humid Atmosphere

LiNi1/3Mn1/3Co1/3O2 compound was successfully synthesized by the co-precipitation method. The effect of H2O on LiNi1/3Mn1/3Co1/3O2 in humid atmosphere was investigated by structural, magnetic and electrochemical analysis. The consequence is that immersion of LiNi1/3Mn1/3Co1/3O2 to H2O and exposure of LiNi1/3Mn1/3Co1/3O2 to humid atmosphere led to a rapid attack in the surface layer of the particles. This effect resulted in the chemical attack of LiNi1/3Mn1/3Co1/3O2 but was restricted only to the surface layer of the particles (10 nm thickness). This aging process occurred during the first few minutes, then it saturated. About 8% of Li-ion was lost due to the delithiation at surface layer. After aging, an initial discharge capacity of 139 mAh/g was delivered at 1 C-rate in the cut-off voltage of 3.0-4.3 V. About 95% of its initial capacity was retained after 30 cycles.