Improved Performances of LiNi_0.8Co_0.15Al_0.05O₂ Material Employing NaAlO₂ as a New Aluminum Source

To prepare a high-performance LiNi 0.8 Co 0.15 Al 0.05 O 2 material (LNCA) for Li-ion batteries, a new aluminum source, NaAlO 2, is employed in the coprecipitation step for the first time, and the effect of aluminum sources on the performances is systematically investigated. Different from the traditional preparation process using Al(NO 3 ) 3 as the aluminum source, the preparation process of the Ni 0.8 Co 0.15 Al 0.05 (OH) 2.05 precursor from NaAlO 2 is a hydrolysis process, during which the fast precipitation of Al 3+ and the formation of a flocculent precipitate can be effectively avoided. As expected, stoichiometric LNCA with uniform element distribution, low cation mixing and well-ordered layered structure is obtained from NaAlO 2, which is designed as LNCA-NaAlO 2 . The characterization and electrochemical measurements show that LNCA-NaAlO 2 exhibits significantly improved performances (such as tap density, initial discharge capacity and volumetric energy density, rate performance, cycle performance, electrochemical stability, microstructure stability, and storage stability) compared to the performances of those prepared from Al(NO 3 ) 3 (LNCA-Al(NO 3 ) 3 ), indicating that it is an effective strategy to preparing high-performance LNCA employing NaAlO 2 as the aluminum source.