Structural and Electrochemical Aspects of LiNi _0.8 Co _0.1 Mn _0.1 O ₂ Cathode Materials Doped by Various Cations

Ni-rich materials of layered structure LiNi _x Co _y Mn _z O ₂ , x > 0.5, are promising candidates as cathodes in high-energy-density Li-ion batteries for electric vehicles. The structural and cycling stability of Ni-rich cathodes can be remarkably improved by doping with a small amount of extrinsic multivalent cations. In this study, we examine development of a fast screening methodology for doping LiNi _0.8 Co _0.1 Mn _0.1 O ₂ with cations Mg ²⁺ , Al ³⁺ , Si ⁴⁺ , Ti ⁴⁺ , Zr ⁴⁺ , and Ta ⁵⁺ by a "top-down" approach. The cathode material is coated by a precursor layer that contains the dopant, which then is introduced into the particles by diffusion during heat treatment at elevated temperatures. The methodology described herein can be applied to Ni-rich cathode materials and allows relatively easy and prompt identification of the most promising dopants. Then further optimization work can lead to development of high-capacity stable cathode materials. The present study marks Ta ⁵⁺ cations as very promising dopants for Ni-rich NCM cathodes.