A novel scalable thinning route to enhance long-term stability of layered cathode materials for Li-ion batteries

A high-pressure micro-fluidization method is applied to layered cathode materials to obtain few-layered nanosheets for the first time. The effect of the micro-fluidization on Li(Ni0.333Mn0.333Co0.333) (NMC) and LiCoO2 is investigated regarding crystal structure, morphology, and electrochemical properties. Micro-fluidization facilitated the exfoliation of LiCoO2 layers thanks to the high shear force. As a result, the exfoliated LiCoO2 nanosheets exhibited preferred orientations with more intense (003) facets. In addition, the oxygen position in the CoO6 octahedra altered, resulting in a shortened Co-O bond length after micro-fluidization. Research demonstrates that micro-fluidized NMC and LiCoO2 exhibited superior cyclic performance compared to the pristine one. Notably, it was found that micro-fluidized LiCoO2 exhibited an improvement in capacity retention (75%) compared to pristine LiCoO2 (21%) after 100 cycles at 0.1C. The enhanced cyclic performance of micro-fluidized NMC and LiCoO2 is attributed to the surface stabilization due to the surface reconstruction of thin plates after micro-fluidization.