Insights into the precursor specific surface area for engineering Co-free Ni-rich cathodes with tailorable properties

Cobalt-free Ni-rich layered oxides have become the most promising cathode candidates owing to their high capacity and environment-friendly characteristics. Although element doping and surface coating strategies could ameliorate the electrochemical performances of cobalt-free Ni-rich cathodes, manufacturing costs are inevitably increased. Especially, regulating precursor features has been regarded as a convenient and economical approach for fabricating desired cathode materials. However, the relationship between precursor trait and properties of cathode has been still unclear. In this work, precursor engineering designed by specific surface area has been proposed for the preparation of Co-free Ni-rich cathodes with tailorable properties, in which the cation mixing could be regulated by capillarity in the lithiation process. It is confirmed that the precursor with larger specific surface area exhibits smaller pore size, ensuring the better wettability and enhanced capillarity for homogeneous lithiation reaction. Triggered by the sufficient lithiation behavior, the synthesized LiNi0.9Mn0.1O2 cathode bearing with low Li+/Ni2+ cation mixing and reduced residual lithium shows the excellent rate ability endowed by fast Li+ diffusion kinetics. Meanwhile, the high cation mixing of LiNi0.9Mn0.1O2 cathode originated from insufficient lithiation reaction could bring out the cation-ordered superlattice structure, which greatly mitigates detrimental phase transition for improving the cycling stability. These novel insights provide a favorable perspective based on precursor tactics for elaborate syntheses of high-performance cobalt-free high-nickel cathode materials.