Tuning of aluminum concentration distribution in high nickel cathode particles for lithium ion batteries

This study focuses on a novel approach for the structural design of LiNi_0.86Co_0.12Al_0.02O₂ cathodes by tailoring the distribution of Al elements using milled-Al(OH)₃. The distribution of Al in the cathode material is investigated using an electron probe micro analyzer. By controlling milled-Al(OH)₃ addition time at 3 and 6 h, thickness of Al-rich layer is varied during co-precipitation process and following calcination with LiOH produces cathode materials with the variant Al distribution. Initial discharge capacities of the cathodes with the Al addition at 3 and 6 h are 202 and 195 mA h g⁻¹ and the IE (initial efficiency) is 92.5 and 86.6%, respectively. The capacity retentions from the cycling test of the individual cathodes are as high as 96.7 and 92.6% at 50 cycles under 1 C rate, respectively. This advanced electrochemical performance is attributed to gradual increase of Al element from inner to outer in active material.