Computational screening of dopants for mitigating degradation behaviors in sodium-ion layered oxide cathode material

Computational screening is performed using calculations based on first-principles to shortlist ideal dopants that can improve the structural and chemical stabilities of sodium-ion layered cathode materials. NaNi0.5Mn0.5O2 is chosen as the reference structure to benchmark the performance of the considered dopants. Several important criteria are considered during screening, and these included the phase stability, phase transition, oxygen stability, dopant activity, and lattice parameters based on previously addressed degradation mechanisms in this type of material. Among the initial 35 candidates, 12 dopants are able to enhance the electrochemical performance of the pristine material. The final ranking is determined by scoring the elements against the set criteria and then summing the scores. Consequently, the top 5 dopants are Hf, Zr, Y, Ti, and Ru. Results from this investigation provide design principles and guidelines to develop highly stable and safe sodium ion batteries. (C) 2020 Elsevier B.V. All rights reserved.