EFFECT OF SYNTHESIS ROUTES ON THE ELECTROCHEMICAL PERFORMANCE OF LiNi_0.6Mn_0.2Co_0.2O₂ MATERIAL FOR LITHIUM ION BATTERIES

Among the cathodes for lithium-ion batteries, Ni-rich LiNi_xMn_yCo_1‑x‑yO₂ (x> 0.5) materials have attracted a attention as promising candidates due to their high capacity, low cost, good cycling stability, and safety. However, the electrochemical performance of cathodes strongly depends on the synthetic methods, resulting in materials with different crystallinity, phase purity, particle morphology, particle size and cation (Li⁺/Ni²⁺) mixing. In the present study, we have demonstrated the effect of synthetic routes, on the improvement of the atomic level uniform distribution of elements and their effect on the electrochemical performance of Ni-rich materials for Li-ion batteries. As Ni/Mn distribution is closely related to synthetic conditions applied for preparing the precursor, the optimizing synthesis process may enhance the uniformity of Ni distribution and thus improve the charge/discharge performance of the Ni-rich cathodes. For this LiNi_0.6Mn_0.2Co_0.2O₂ was synthesized by different routes namely, freeze drying, self-combustion and solid-state methods and these results are compared with commercial materials. The influence of synthetic routes on the crystal structure, morphology, and electrochemical performance of the samples was characterized by X-ray diffraction, scanning electron microscopy, galvanostatic cycling, and impedance tests. We established that all synthesized samples showed a typical hexagonal structure with a single phase, R-3m symmetry group. It was demonstrated that variation in synthetic routes resulted in the change of the electrochemical performance, such as reversible capacity, the rate capability, and impedance. The material prepared by freeze-drying route exhibited superior electrochemical properties compared to the self-combustion technique, solid-state method and a commercial sample. The results obtained will be discussed at the of presentation.