Diffusion mechanism in the sodium-ion battery material sodium cobaltate

DOI: 10.1038/s41598-018-21354-5

Authors: T. J. Willis (Royal Holloway, University of London; ISIS Facility) , D. G. Porter (Diamond Light Source) , D. J. Voneshen (ISIS Facility) , S. Uthayakumar (Royal Holloway, University of London) , F. Demmel (ISIS Facility) , M. J. Gutmann (ISIS Facility) , M. Roger (Service de Physique de l’Etat Condensé) , K. Refson (Royal Holloway, University of London; ISIS Facility) , J. P. Goff (Royal Holloway, University of London)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Scientific Reports , VOL 8

State: Published (Approved)
Published: February 2018

Abstract: High performance batteries based on the movement of Li ions in Li x CoO2 have made possible a revolution in mobile electronic technology, from laptops to mobile phones. However, the scarcity of Li and the demand for energy storage for renewables has led to intense interest in Na-ion batteries, including structurally-related Na x CoO2. Here we have determined the diffusion mechanism for Na0.8CoO2 using diffuse x-ray scattering, quasi-elastic neutron scattering and ab-initio molecular dynamics simulations, and we find that the sodium ordering provides diffusion pathways and governs the diffusion rate. Above T ~ 290 K the so-called partially disordered stripe superstructure provides channels for quasi-1D diffusion, and melting of the sodium ordering leads to 2D superionic diffusion above T ~ 370 K. We obtain quantitative agreement between our microscopic study of the hopping mechanism and bulk self-diffusion measurements. Our approach can be applied widely to other Na- or Li-ion battery materials.

Journal Keywords: Batteries; Structure of solids and liquids

Diamond Keywords: Batteries; Lithium-ion

Subject Areas: Materials, Chemistry, Energy

Facility: ISIS

Added On: 19/02/2018 14:54

Documents:
s41598-018-21354-5.pdf

Discipline Tags:

Energy Storage Energy Physical Chemistry Energy Materials Chemistry Materials Science

Technical Tags: