Preparation and characterization of LiNi0.8Co0.15Al0.05O2 with high cycling stability by using AlO2- as Al source.

We report the preparation of a series of LiNi 0.8 Co 0.15 Al 0.05 O 2 materials with different reaction time (10, 20, 30 and 40 h) of precursor and their electrochemical properties as cathode material for lithium-ion batteries (LIBs). The preparation of LiNi 0.8 Co 0.15 Al 0.05 O 2 was divided into two steps: a co-precipitation process to obtain Ni 0.8 Co 0.15 Al 0.05 (OH) 2 precursor and a calcination step with LiOH. During the co-precipitation process, AlO 2 - was employed as Al source so as to guarantee Ni 2+ , Co 2+ and Al 3+ co-precipitation. The impacts of different synthesis time of the precursor on crystal structure, morphology and electrochemical performance of LiNi 0.8 Co 0.15 Al 0.05 O 2 were systematically investigated. The samples with various synthesis time of precursor possessed spherical morphology and a layered α-NaFeO 2 structure with R-3m space group. Especially, when the reaction time of precursor was 30 h, the LiNi 0.8 Co 0.15 Al 0.05 O 2 had the weakest degree of Li + /Ni 2+ ions mixing and the best uniformity and integrity. When used as cathode materials for LIBs, the LiNi 0.8 Co 0.15 Al 0.05 O 2 with 30 h exhibited high discharge capacity, good cycling performance and remarkable rate capability. The maximum discharge capacity was 202.3 mAh g −1 at 0.1 C and the capacity retention approached 99.4% after 100 cycles at 1 C. At 10 C, the discharge capacity exceeded 140 mAh g −1 , suggesting a possible application in the high rate LIBs. The excellent electrochemical performance might be attributed to the uniform co-precipitation of Ni 2+ , Co 2+ and Al 3+ and well layered structure with less Li + /Ni 2+ mixing. [ABSTRACT FROM AUTHOR]