Jump to main content
Jump to site search

Issue 17, 2019
Previous Article Next Article

Phase transformations and capacity fade mechanism in LixSn nanoparticle electrodes revealed by operando 7Li NMR

Author affiliations

Abstract

Operando 7Li nuclear magnetic resonance (NMR), ex situ7Li magic-angle spinning (MAS) NMR and pair distribution function (PDF) methods are used to investigate the electrochemical lithiation and delithiation of 60 nm particles of tin. While the structural transformation pathways between Li–Sn intermetallics during lithiation and delithiation of Sn nanoparticles are somewhat consistent with the structural evolution of Li–Sn phases expected from the equilibrium binary phase diagram, there are some notable exceptions with the observation of a metastable phase Li2Sn3, and two vacancy rich metastable phases, Li7−ζSn3, and Li13−δSn5 during delithiation. The capacity fade of ∼30% per cycle is not attributed to particle cracking, but rather to particles losing contact with the carbon/PVDF binder. The disconnecting particles are associated with LixSn phases undergoing large decreases in diameters on delithiation, i.e., Sn, Li2Sn5, LiSn, and Li7Sn3. A peculiar behavior of capacity fade in this system is that it only occurs during delithiation. This is explained by a model of disconnecting–reconnecting LixSn-containing particles which remain in the electrode and become reconnected every cycle by the volume increase of neighboring connected particles during the lithiation process.

Graphical abstract: Phase transformations and capacity fade mechanism in LixSn nanoparticle electrodes revealed by operando 7Li NMR

Back to tab navigation

Supplementary files

Article information


Submitted
26 Feb 2019
Accepted
01 Apr 2019
First published
01 Apr 2019

J. Mater. Chem. A, 2019,7, 10781-10794
Article type
Paper
Author version available

Phase transformations and capacity fade mechanism in LixSn nanoparticle electrodes revealed by operando 7Li NMR

J. L. Lorie Lopez, P. J. Grandinetti and A. C. Co, J. Mater. Chem. A, 2019, 7, 10781 DOI: 10.1039/C9TA03345A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.


Social activity

Search articles by author

Spotlight

Advertisements