Unraveling the roles of Al, Mn and Co in the Ni-rich cathode material for Li-ion batteries

Abstract

Ni-rich layered cathode materials have received extensive attention due to their high energy density. However, the roles of Al, Mn and Co have not been uniformly reported so far. In this work, the roles of Al, Mn and Co in the Ni-rich cathode are studied using first-principles calculations. The results show that Al and Co doping can improve the rate performance of the cathode. Mn doping is beneficial to improve the intercalation potential and reduce the volume change of the active material during charging/discharge. In Ni-rich cathode materials, Li-ions located on the linear s-p orbital are more likely to exchange with Ni ions. The linear s-p orbital are distorted after Al, Mn and Co doping, thereby suppressing cation mixing. Due to the stronger interaction between Al and O, dopant Al is also beneficial to stabilize the oxygen of the active material. This theoretical study gives new insight about the roles of Al, Mn and Co in Ni-rich cathode materials, and will help in designing high-performance cathode materials.