Slug flow synthesis of NCMA: Effect of substitution of cobalt with aluminum on the electrochemical performance of Ni-rich cathode for lithium-ion battery

Nickle-rich Li[Ni1-x-yCoxMny]O2 (x, y ≤ 0.1) (NCM) layered materials are known as promising cathode materials for next-generation lithium-ion batteries and electric vehicles owing to their high reversible capacity and high operating voltage of up to 3.6 vs Li/Li+. However, issues, such as irreversible phase transition, cation mixing, microcrack formation, thermal and structural stability of the material prevent its widespread adoption. Although, cation doping is a well-known technique to enhance the electrochemical performance of the NCM-based cathode material, the performance of the material is very sensitive to the doping amount. In this study, three Al-doped quaternary Ni-rich cathode materials Li[Ni0.85Co(0.1-x)Mn0.05Alx]O2 (where, x= 0 - 0.04) (NCMA) are synthesized through three-phase slug-flow based continuous manufacturing process followed by high temperature calcination to study the effect of Al-doping on the performance of the cathode material while reducing Co. The slug flow-based production platform has several advantages, like particle size uniformity, high production rate, and homogeneity in elemental distribution. It is found that with an increase in Al content, the specific capacity decreases but the cyclic stability and rate capability increases. Optimum Al-doping not only compensates for the adverse effect of low Co by decreasing the extent of cation mixing but also minimizes the electrode polarization and cracking of the particles.