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A Chemical Map of NaSiCON Electrode Materials for Sodium-ion Batteries

preprint
submitted on 23.10.2020, 15:12 and posted on 27.10.2020, 06:42 by Baltej Singh Gill, Ziliang Wang, Sunkyu Park, Gopalakrishnan Sai Gautam, Jean-Nöel Chotard, Laurence Croguennec, Dany Carlier, Anthony K. Cheetham, Christian Masquelier, Pieremanuele Canepa

Na-ion batteries are promising devices for smart grids and electric vehicles due to cost effectiveness arising from the overall abundance of sodium (Na) and its even geographical distribution. Among other factors, the energy density of Na-ion batteries is limited by the positive electrode chemistry. NaSICON-based positive electrode materials are known for their wide range of electrochemical potentials,[1],[2],[3] high ionic conductivity, and most importantly their structural and thermal stabilities. Using first- principles calculations, we chart the chemical space of 3d transition metal-based NaSICON phosphates of formula NaxMM’(PO4)3 (with M and M’= Ti, V, Cr, Mn, Fe, Co and Ni), to analyze their thermodynamic stabilities and the intercalation voltages for Na+ ions. Specifically, we computed the Na insertion voltages and related properties of 28 distinct NaSICON compositions. We investigated the thermodynamic stability of Na-intercalation in previously unreported NaxMn2(PO4)3 and NaxVCo(PO4)3. The calculated quaternary phase diagrams of the Na-P-O-Co and Na-P-O-Ni chemical systems explain the origin of the suspected instability of Ni and Co-based NaSICON compositions. From our analysis, we are also able to rationalize anomalies in previously reported experimental data in this diverse and important chemical space.

Funding

French National Research Agency and National Research Foundation ANR-NRF NRF2019-NRF- ANR073 Na-MASTER.

National Research Foundation under his NRF Fellowship NRFF12-2020-0012

French National Research Agency (STORE-EX Labex Project ANR-10-LABX-76-01)

History

Email Address of Submitting Author

pcanepa@nus.edu.sg

Institution

National University of Singapore

Country

Singapore

ORCID For Submitting Author

0000-0002-5168-9253

Declaration of Conflict of Interest

N.A

Exports