Beyond Doping and Coating: Prospective Strategies for Stable High-Capacity Layered Ni-Rich Cathodes

This Perspective discusses the prospective strategies for overcoming the stability and capacity trade-off associated with increased Ni content in layered Ni-rich Li­[Ni_xCo_yMn_z]­O₂ (NCM) and Li­[Ni_xCo_yAl_z]­O₂ (NCA) cathodes. The Ni-rich NCM and NCA cathodes have largely replaced the LiCoO₂ cathodes in commercial batteries because of their lower cost, higher energy density, good rate capability, and reliability that has been extensively field-tested. Nevertheless, they suffer from microcrack generation along grain boundaries and Ni^3+/4+ reactivity that rapidly deteriorate electrochemical performance. Doping and coating have been efficient strategies in delaying the onset of the damage, but they fail to overcome the degradation. There are, however, alternative strategies that directly counter the inherent degradation through micro- and nanostructural modifications of the Ni-rich NCM and NCA cathodes.