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Computational Study of NaVOPO4 Polymorphs as Cathode Materials for Na-Ion Batteries: Diffusion, Electronic Properties, and Cation-Doping Behavior

Lookup NU author(s): Dr James DawsonORCiD

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This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Abstract

© 2018 American Chemical Society.Rechargeable sodium-ion batteries have gained considerable interest as potential alternatives to lithium-ion batteries, owing to their low cost and the wide abundance of sodium. Phosphate compounds are promising materials for sodium-ion batteries because of their high structural stability. Vanadium phosphates have shown high energy densities as cathode materials, but their Na-ion transport and cation-doping properties are not as yet fully understood. Here, we have combined density functional theory calculations and molecular dynamics techniques to study the diffusion, electronic properties, and cation doping of the α-, β-, and αI-NaVOPO4 polymorphs. The calculated Na-ion activation energies of these compounds (0.3-0.5 eV) are typical for Na-based cathode materials and the simulations predict Na-ion diffusion coefficients of 10-11-10-12 cm2 s-1. The cell voltage trends show an operating range of 3.1-3.3 V vs Na/Na+, with the partial substitution of vanadium by other metals (Al3+, Co2+, Fe3+, Mn4+, Ni2+, or Ti4+) increasing the cell voltage by up to 0.2-1.0 V vs Na/Na+. Our study provides new quantitative insights into the electrochemical behavior of a potentially important class of phosphate cathode materials for sodium-ion batteries.


Publication metadata

Author(s): Aparicio PA, Dawson JA, Islam MS, De Leeuw NH

Publication type: Article

Publication status: Published

Journal: Journal of Physical Chemistry C

Year: 2018

Volume: 122

Issue: 45

Pages: 25829-25836

Print publication date: 15/11/2018

Online publication date: 02/10/2018

Acceptance date: 10/08/2018

Date deposited: 15/01/2020

ISSN (print): 1932-7447

ISSN (electronic): 1932-7455

Publisher: American Chemical Society

URL: https://doi.org/10.1021/acs.jpcc.8b07797

DOI: 10.1021/acs.jpcc.8b07797


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Funding

Funder referenceFunder name
EP/K016288
EP/L000202

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