Synthesis and stored performance of LiNi0.8Co0.17Al0.03O2 cathode material prepared by using a flocculation precipitation process

Abstract Layered lithium nickel cobalt aluminum oxides cathode materials (α-NaFeO2 structure, Space group: R-3 m) are prepared using an unusual flocculation precipitation process. The synthesis strategy utilized the new aluminum precursor containing nickel, cobalt and aluminum hydroxides has a different mechanism from that for conventional coprecipitation process. As-prepared LiNi0.85Co0.17Al0.03O2 delivers a first cycle capacity of 164 mAh g−1 at 1C rate. The stored sample delivers a first cycle capacity of 146 mAh g−1 and the capacity retention rate of 93% in 40 cycles at 1C rate. Its stored cell exhibits a capacity of 99 mAh g−1 at 1C rate. The particle surface of the sample has a coating layer of Li3.62aLi4.31bNi0.172+Ni0.833+Co0.062+Al0.373+O0.98aO12.6b (with the structure of Li2CO3, LiAl5O8 and α-NaFeO2). The coating layer can prevent the reaction between the particles and moisture in the air or the particles and electrolytes in the cell at 55 °C. Therefore, LiNi0.85Co0.17Al0.03O2 exhibits excellent rate performance and stored one for its low polarization, high stability α-NaFeO2 structure and high stable coating layer. The exceptional overall performance of the as-synthesized LiNi0.85Co0.17Al0.03O2 presents itself a promising cathode material for next generation lithium-ion batteries.