Synthesis and characterization of LiNi_(0.95-x)Co_xAl_(0.05)O_2 for lithium-ion batteries

Samples of LiNi0.95-xCoxAl0.05O2（x=0.10 and 0.15） and LiNiO2,synthesized by the solid-state reaction at 725?℃ for 24?h from LiOH·H2O,Ni2O3,Co2O3,and Al（OH）3 under an oxygen stream,were characterized by TG-DTA,XRD,SEM,and electrochemical tests. Simultaneous doping of cobalt and aluminum at the Ni-site in LiNiO2 was tried to improve the cathode performance for lithium-ion batteries. The results showed that co-doping （especially,5% Al and 10% Co in atomic fraction） definitely had a large beneficial effect in increasing the capacity （186.2?mA·h/g of the first discharge capacity for LiNi 0.85 Co 0.1 0Al 0.05 O2） and cycling behavior (180.1?mA·h/g after 10 cycles for LiNi0.95-xCoxAl0.05O2) compared with 180.7?mA·h/g of the first discharge capacity and 157.7?mA·h/g of the tenth discharge capacity for LiNiO2,respectively. Differential capacity versus voltage curves showed that the co-doped LiNi0.95-xCoxAl0.05O2 had less intensity of the phase transitions than the pristine LiNiO2.

Samples of LiNi0.95-xCoxAl0.0502（x = 0.10 and 0.15） and LiNiO2, synthesized by the solid-state reaction at 725 ℃ for 24 h from LiOH·H2O, Ni2O3, Co2O3, and Al（OH）3 under an oxygen stream, were characterized by TG-DTA, XRD, SEM, and electrochemical tests. Simultaneous doping of cobalt and aluminum at the Ni-site in LiNiO2 was tried to improve the cathode performance for lithium-ion batteries. The results showed that co-doping （especially, 5 % A1 and 10 % Co in atomic fraction） .