Long-Life Ni-Rich NMC Cathodes with Heterogeneous Particle Structure Using Advanced High-Speed Synthesis Process

Abstract

Layered Ni-rich cathode material, Li[NixMnyCo1−x−y]O2 (x ≥ 0.8), is one of the most prospective materials for rechargeable lithium-ion batteries (LIBs) due to its high capacity. However, significant challenges remain in order to improve capacity retention during cycling and thermal-abuse tolerance of this material. As one of the promising approaches to overcome barriers, a series of core-shell structured cathode materials with the overall bulk composition of LiNi0.8Mn0.1Co0.1O2 is produced via co-precipitation method where Ni-rich composition (LiNi0.9Mn0.05Co0.05O2) with higher capacity is particle core and Mn-rich composition with higher stability is particle surface. It is challenging to design and implement heterogeneous structured particles with synergistic effects by combining the advantages of each composition. It is particularly important to develop a process of producing economically and quickly each type of these cathode particles, in which the Ni-rich composition and the Mn-rich composition change continuously or discretely from the particle core to the particle surface. To achieve this goal, a continuous rapid synthesis process for the production of heterogeneous structured cathodes was developed at ANL MERF based on an advanced Continuous Stirred Tank Reactor (CSTR) system and a Taylor Vortex Reactor (TVR) system. A detailed description of the developed process to mass-produce heterogeneous structured materials economically and rapidly will be presented. The excellent physical and electrochemical properties of Ni-rich NMC cathodes with core-shell or core-gradient particle structures produced by this advanced process will be reported. The produced heterogeneous structured cathodes and commercially available normal NMC materials will be compared through analysis of coin half cell, pouch full cell, SEM, EDS, ICP-MS, DSC, EIS, and other advanced characterization techniques.