The University of Southampton
University of Southampton Institutional Repository

Direct observation of active material concentration gradients and crystallinity breakdown in LiFePO4 electrodes during charge/discharge cycling of lithium batteries

Direct observation of active material concentration gradients and crystallinity breakdown in LiFePO4 electrodes during charge/discharge cycling of lithium batteries
Direct observation of active material concentration gradients and crystallinity breakdown in LiFePO4 electrodes during charge/discharge cycling of lithium batteries
The phase changes that occur during discharge of an electrode comprised of LiFePO4, carbon, and PTFE binder have been studied in lithium half cells by using X-ray diffraction measurements in reflection geometry. Differences in the state of charge between the front and the back of LiFePO4 electrodes have been visualized. By modifying the X-ray incident angle the depth of penetration of the X-ray beam into the electrode was altered, allowing for the examination of any concentration gradients that were present within the electrode. At high rates of discharge the electrode side facing the current collector underwent limited lithium insertion while the electrode as a whole underwent greater than 50% of discharge. This behavior is consistent with depletion at high rate of the lithium content of the electrolyte contained in the electrode pores. Increases in the diffraction peak widths indicated a breakdown of crystallinity within the active material during cycling even during the relatively short duration of these experiments, which can also be linked to cycling at high rate.
1932-7447
6548-6557
Roberts, Matthew R.
773cf85a-e589-406f-8c75-505f6930bd3d
Madsen, Alex
1d4678e9-0d8d-4d87-ba22-7fcc109570ce
Nicklin, Chris
e4ca187c-5eef-48a2-8f36-aef2bc27ea4f
Rawle, Jonathan
9925245e-4222-48b2-8900-22a2b1e086b1
Palmer, M.
3d216857-94a6-42be-a372-8ac69541cb1c
Owen, John R.
067986ea-f3f3-4a83-bc87-7387cc5ac85d
Hector, Andrew L.
f19a8f31-b37f-4474-b32a-b7cf05b9f0e5
Roberts, Matthew R.
773cf85a-e589-406f-8c75-505f6930bd3d
Madsen, Alex
1d4678e9-0d8d-4d87-ba22-7fcc109570ce
Nicklin, Chris
e4ca187c-5eef-48a2-8f36-aef2bc27ea4f
Rawle, Jonathan
9925245e-4222-48b2-8900-22a2b1e086b1
Palmer, M.
3d216857-94a6-42be-a372-8ac69541cb1c
Owen, John R.
067986ea-f3f3-4a83-bc87-7387cc5ac85d
Hector, Andrew L.
f19a8f31-b37f-4474-b32a-b7cf05b9f0e5

Roberts, Matthew R., Madsen, Alex, Nicklin, Chris, Rawle, Jonathan, Palmer, M., Owen, John R. and Hector, Andrew L. (2014) Direct observation of active material concentration gradients and crystallinity breakdown in LiFePO4 electrodes during charge/discharge cycling of lithium batteries. The Journal of Physical Chemistry C, 118 (13), 6548-6557. (doi:10.1021/jp411152s).

Record type: Article

Abstract

The phase changes that occur during discharge of an electrode comprised of LiFePO4, carbon, and PTFE binder have been studied in lithium half cells by using X-ray diffraction measurements in reflection geometry. Differences in the state of charge between the front and the back of LiFePO4 electrodes have been visualized. By modifying the X-ray incident angle the depth of penetration of the X-ray beam into the electrode was altered, allowing for the examination of any concentration gradients that were present within the electrode. At high rates of discharge the electrode side facing the current collector underwent limited lithium insertion while the electrode as a whole underwent greater than 50% of discharge. This behavior is consistent with depletion at high rate of the lithium content of the electrolyte contained in the electrode pores. Increases in the diffraction peak widths indicated a breakdown of crystallinity within the active material during cycling even during the relatively short duration of these experiments, which can also be linked to cycling at high rate.

Other
jp411152s - Version of Record
Available under License Other.
Download (5MB)

More information

e-pub ahead of print date: 26 February 2014
Published date: 3 April 2014
Organisations: Electrochemistry

Identifiers

Local EPrints ID: 366638
URI: http://eprints.soton.ac.uk/id/eprint/366638
ISSN: 1932-7447
PURE UUID: c9879a02-a541-47c0-b1ca-ffceaeed8fa9
ORCID for John R. Owen: ORCID iD orcid.org/0000-0002-4938-3693
ORCID for Andrew L. Hector: ORCID iD orcid.org/0000-0002-9964-2163

Catalogue record

Date deposited: 07 Jul 2014 10:37
Last modified: 15 Mar 2024 02:52

Export record

Altmetrics

Contributors

Author: Matthew R. Roberts
Author: Alex Madsen
Author: Chris Nicklin
Author: Jonathan Rawle
Author: M. Palmer
Author: John R. Owen ORCID iD

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×