Synthesis of Single Crystal LiNi_0.92Co_0.06Mn_0.01Al_0.01O₂Cathode Materials with Superior Electrochemical Performance for Lithium Ion Batteries

Compared to conventional polycrystallines, single crystal layered cathode materials exhibit the excellent structural and thermal stability, storage and lifetime at high voltage and elevated temperature. However, these single crystal materials are less reported, especially for Ni ≥ 0.92 in nickel-rich cathode materials. In this paper, single crystal LiNi0.92Co0.06Mn0.01Al0.01O2 (NCMA) cathode materials are researched. The experiment demonstrates that co-doping fluxing agents in B-NCMA (NCMA with 1000ppm W and 1000 ppm Mo) sample facilitate to generate uniform and small crystal size, which delivers a high initial discharge capacity of 221.4 mAh g-1 at 0.1 C. Moreover, the superior capacity retention of 94.9% after 100th cycle at 45 °C is obtained. Furthermore, DSC analysis of cycled B-NCMA material displays high thermal release temperature and low gas emission, revealing decent thermal stability. XRD, dQ•dV-1 and EIS results suggest that co-doping fluxing agents beneficial to form less cationic mixing, more stable phase structure and less internal resistance, respectively, which are associated with excellent rate capacity, cycling and thermal stability of single crystal NCMA. In our opinion, this study will stimulate that more fluxing agents are found and applied on single crystal nickel-rich cathode materials, which will have a bright future in the high-energy lithium ion battery fields.