Regulating Cation Disorder Triggered-Electronic Reshuffling for Sustainable Conventional Layered Oxide Cathodes

Unraveling the underlying thermodynamic principles governing the sustainable conventional layered cathodes at the electron-scale remains a critical challenge, yet it is essential for advancing Li-ion batteries toward a high energy density future. In this context, the layered Li x Ni 1/3 Co 1/3 Mn 1/3 O 2 is taken as an example to disclose the intricate connection among the structural disorders, electronic transfer, redox chemistry, and performance degradation using ab initio calculations. During cation disordering, the dramatic picture of electronic reshuffling is sculpted by the appearance of electron trapping centers/parasitic holes in the local TM-rich domain, as well as the O:2p lone-pairs in the local Li-rich domain. Distinct redox processes emerge wherein the parasitic holes can effectively couple with the adjacent transition metal (TM:d electron) and/or the oxygen ions (O:2p lone-pairs) depending on the states of charge. Regarding the structural stability, the electronic reshuffling induces a reciprocal relationship between cation disorder and oxygen stability, posing a concealed threat of reversibility. A new self-sustaining process is conceived as the primary pathway for severe layered damages and degradation. Notably, the cation disorder triggered-electronic reshuffling exhibits strict regularity that depends on the relative energies of the TM:d and O:2p states, holding promise for the reasonable design of sustainable layered cathodes. The theoretical framework provides a novel and self-consistent description of the thermodynamic conditions toward the reversible electrochemical process for conventional layered cathodes.