An oxide precursor route for manufacturing nickel-rich NCM cathode materials through the flame synthesis approach

During the current co-precipitation wet chemistry methods, the Ni-Co-Mn hydroxide precursor is initially prepared, which undergo high-temperature decomposition in calcination process, forming the corresponding Ni-Co-Mn oxides to mix with lithium salts, eventually leading to the synthesis of cathode materials, LiNi_xCo_yMn_1-x-yO₂ (NCM). The above hydroxide precursor route for the preparation of NCM cathode materials usually result in multiple unit operations, substantial liquid wastes, strong base contamination, and high resources consumption. The present study aims at proposing an alternative oxide precursor route for manufacturing NCM cathode materials through the flame synthesis (FS) approach, to alleviate the above issues of the usual wet chemistry methods. Specifically, based on a co-flow diffusion flame burner, the Ni-Co-Mn oxides was prepared by FS, and the as-synthesized oxide precursor, without any treatment, was then mixed with lithium carbonate (Li₂CO₃) to undergo calcination, leading to the successful preparation of the nickel-rich NCM811 cathode materials. Results show that the oxide precursor of NCM811, Ni_0.8Co_0.1Mn_0.1O_1.1, is composed of a primary NiO rock salt phase and secondary spinel-structured phases similar to NiCo₂O₄ and NiMn₂O₄, with rough surface, spherical structure, particle size of about 1.2 ​μm, and uniform distribution of the elements. The initial discharge specific capacity of the resulting NCM811 cathode materials achieve as high as 194.7 mAh/g, with capacity retention being 87.1 ​% after 100 cycles, which is superior to that of commercial samples or prepared by other methods as reported in literatures. Overall, the Ni-Co-Mn oxides precursor route through FS is compelling to the preparation of nickel-rich NCM cathode materials.