High-throughput computational screening of dopants for improved structural stability in overlithiated layered oxide cathodes

초록

Overlithiated layered oxides (OLOs) that achieve high specific capacity (>250 mAh/g) owing to additional anionic redox are promising cathode materials for lithium rechargeable batteries. However, the anionic redox at high voltages leads to structural degradation of OLO with transition metal (TM) migration and oxygen loss. Such structural instability leads to voltage and capacity fading, which impedes the commercial use of OLO. In this study, first-principles-based high-throughput computational screening is performed to identify promising dopants to improve the structural stability of OLO. Li1.15Ni0.19Co0.11Mn0.56O2 is constructed as a pristine structure to evaluate the performances of the 36 dopants. Several criteria, including thermodynamic stability, TM-O bond length, interlayer spacing, volumetric shrinkage, oxygen stability, dopant inertness, and specific energy, are considered in the discharged and charged states. Among the considered dopant candidates, two (Si and Ga) fulfill all the criteria; hence, they are believed to improve the structural stability of the OLO cathode. The current analysis provides comprehensive guidelines for the synthesis of doped OLO while satisfying long-term cyclability and high-energy requirements.

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