Comparison of structural and electrochemical properties of LiNi0.8Co0.15Al0.05O2 with Li site doping by different cations

Nickel-rich cathode materials are widely used for electronic devices because of their high capacity and rate performance. However, structural deterioration after long-term cycling leads to a significant decline in capacity and cycle life. In this work, the effects of three different cations doping on the structural stability and electrochemical performance of Ni-rich cathode materials were investigated. XRD characterization reveals that doped cation leads to broadening of the distance between Li layers and inhibiting Li+/Ni2+ mixing arrangement. Compared with Na+ and K+, the high valence Mg2+ provides a stronger Mg-O bond, which can effectively restrain the undesired phase transition and sustain the ordered structure. Electrochemical tests demonstrate that NCA with Mg doping has better cycle stability and rate performance than Na and K. The capacity retention rate of NCA with 1% Mg doping is 87.7% after 200 cycles at 1C, and it can still provide a specific capacity of 146.8 mAh g-1 at a high rate of 5C.

Automated summary

Doping different cations can enhance the structural stability and electrochemical performance of nickel-rich cathode materials. The high valence Mg2+ doping provides a stronger bond, effectively suppressing undesired phase transitions. NCA with Mg doping exhibits better cycle stability and rate performance.