Phase Stability and Sodium-Vacancy Orderings in a NaSICON Electrode

Wang, Z.; Park, S.; Deng, Z.; Carlier, D.; Chotard, J.-N.; Croguennec, L.; Gautam, G. S.; Cheetham, A. K.; Masquelier, C.; Canepa, P.

doi:10.1039/D1TA09249A

Phase Stability and Sodium-Vacancy Orderings in a NaSICON Electrode

Z. Wang, S. Park, Z. Deng, D. Carlier, J.-N. Chotard, L. Croguennec, G. S. Gautam, A. K. Cheetham, C. Masquelier, and P. Canepa; J. Mater. Chem. A 10, 209 (2022).

BibTeX

@article{Wang2022phase,
  author  = {Wang, Z. and Park, S. and Deng, Z. and Carlier, D. and Chotard, J.-N. and Croguennec, L. and Gautam, G. S. and Cheetham, A. K. and Masquelier, C. and Canepa, P.},
  title   = {{Phase Stability and Sodium-Vacancy Orderings in a NaSICON Electrode}},
  journal = {Journal of Materials Chemistry A},
  volume  = {10},
  pages   = {209},
  year    = {2022},
  doi     = {10.1039/D1TA09249A}
}

Abstract

We elucidate the thermodynamics of sodium (Na) intercalation into the sodium super-ionic conductor (NaSICON)-type electrode, Na_xV₂(PO₄)₃, for promising Na-ion batteries with high-power density. This is the first report of a computational temperature-composition phase diagram of the NaSICON-type electrode Na_xV₂(PO₄)₃. Based on our computational data, we identify a thermodynamically stable phase with a composition of Na₂V₂(PO₄)₃ and describe its structural features. We also identify another metastable configuration that can occur at room temperature, namely Na_3.5V₂(PO₄)₃. We unveil the crystal-structure and the electronic-structure origins of the ground-state compositions associated with specific Na/vacancy arrangements, which are driven by charge orderings on the vanadium sites. These results are significant for the optimization of high-energy and power density electrodes for sustainable Na-ion batteries.