Facile Mn surface doping of Ni-rich layered cathode materials for lithium ion batteries.

A facile Mn surface doping process is proposed to improve the structural and thermal stability of Ni-rich layered cathode materials (Ni ≥ 80%) for lithium-ion batteries (LIBs) in electric vehicles. In this work, we demonstrate that the surface structure of Ni-rich layered cathode materials can be stabilized by the introduction of a thin Mn-rich surface layer. This layer effectively reduces the direct exposure of highly reactive Ni at the surface, thus improving thermal stability and mitigating side reactions associated with a highly reactive Ni that cause the loss of reversible capacity. In practice, the Mn-surface-doped Ni-rich layered cathode material exhibits a high reversible capacity with an improved cycle performance even at a high operating temperature of 60 °C. We believe that our simple approach offers more opportunities to upscale production without any extra caution.