uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
A stable graphite negative electrode for the lithium-sulfur battery
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
2015 (English)In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 51, no 96, 17100-17103 p.Article in journal (Refereed) Published
Place, publisher, year, edition, pages
2015. Vol. 51, no 96, 17100-17103 p.
National Category
Chemical Sciences
Identifiers
URN: urn:nbn:se:uu:diva-267760DOI: 10.1039/C5CC06666BISI: 000367469400011PubMedID: 26451894OAI: oai:DiVA.org:uu-267760DiVA: diva2:874234
Funder
Swedish Research Council, 2012-3837VINNOVA
Available from: 2015-11-26 Created: 2015-11-26 Last updated: 2017-12-01Bibliographically approved
In thesis
1. Functional Binders at the Interface of Negative and Positive Electrodes in Lithium Batteries
Open this publication in new window or tab >>Functional Binders at the Interface of Negative and Positive Electrodes in Lithium Batteries
2015 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

In this thesis, electrode binders as vital components in the fabrication of composite electrodes for lithium-ion (LIB) and lithium-sulfur batteries (LiSB) have been investigated.

Poly(vinylidene difluoride) (PVdF) was studied as binder for sulfur-carbon positive electrodes by a combination of galvanostatic cycling and nitrogen absorption. Poor binder swelling in the electrolyte and pore blocking in the porous carbon were identified as origins of low discharge capacity, rendering PVdF-based binders an unsuitable choice for LiSBs. More promising candidates are blends of poly(ethylene oxide) (PEO) and poly(N-vinylpyrrolidone) (PVP). It was found that these polymers interact with soluble lithium polysulfide intermediates generated during the cell reaction. They can increase the discharge capacity, while simultaneously improving the capacity retention and reducing the self-discharge of the LiSB. In conclusion, these binders improve the local electrolyte environment at the electrode interface.

Graphite electrodes for LIBs are rendered considerably more stable in ‘aggressive’ electrolytes (a propylene carbonate rich formulation and an ether-based electrolyte) with the poorly swellable binders poly(sodium acrylate) (PAA-Na) and carboxymethyl cellulose sodium salt (CMC-Na). The higher interfacial impedance seen for the conventional PVdF binder suggests a protective polymer layer on the particles. By reducing the binder content, it was found that PAA-Na has a stronger affinity towards electrode components with high surface areas, which is attributed to a flexible polymer backbone and a higher density of functional groups.

Lastly, a graphite electrode was combined with a sulfur electrode to yield a balanced graphite-sulfur cell. Due to a more stable electrode-electrolyte interface the self-discharge of this cell could be reduced and the cycle life was extended significantly. This example demonstrates the possible benefits of replacing the lithium metal negative electrode with an alternative electrode material.

Place, publisher, year, edition, pages
Uppsala: Uppsala universitet, 2015. 58 p.
Keyword
binder, lithium-sulfur batteries, graphite, lithium-ion batteries
National Category
Physical Chemistry Polymer Chemistry Materials Chemistry
Research subject
Chemistry with specialization in Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-267557 (URN)
Presentation
2015-12-16, 2005, Department of Chemistry - Ångström, Lägerhyddsvägen 1, Uppsala, 16:15 (English)
Opponent
Supervisors
Available from: 2015-11-26 Created: 2015-11-24 Last updated: 2015-11-26Bibliographically approved
2. Polymers at the Electrode-Electrolyte Interface: Negative Electrode Binders for Lithium-Ion Batteries
Open this publication in new window or tab >>Polymers at the Electrode-Electrolyte Interface: Negative Electrode Binders for Lithium-Ion Batteries
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

We are today experiencing an increasing demand for high energy density storage devices like the lithium-ion battery for applications in portable electronic devices, electric vehicles (EV) and as interim storage for renewable energy. High capacity retention and long cycle life are prerequisites, particularly for the EV market. The key for a long cycle life is the formation of a stable solid-electrolyte interphase (SEI) layer on the surface of the negative electrode, which typically forms on the first cycles due to decomposition reactions at the electrode-electrolyte interface. More control over the surface layer can be gained when the layer is generated prior to the battery operation. Such a layer can be tailored more easily and can reduce the loss of lithium inventory considerably. In this context, water-soluble electrode binders, e.g. sodium carboxymethyl cellulose (CMC-Na) and poly(acrylic acid) (PAA), have proven themselves exceptionally useful. Since the binder is a standard component in composite electrodes anyway, its integration into the electrode fabrication process is easily accomplished.

This thesis work investigates the parameters that govern binder distribution in elec-trode coatings, control the stability and electrochemical performance of the elec-trode and that determine the composition of the surface layer. Several commonly used electrode materials (graphite, silicon and lithium titanate) have been applied in order to study the impact of the binder on the electrode morphology and the differ-ent electrode-electrolyte interfaces. The results are correlated with the electrochemi-cal performance and with the SEI composition obtained by in-house and synchro-tron-based photoelectron spectroscopy (PES).

The results demonstrate that the poor swellability of these water-soluble binders leads to a protection of the active material, given that the surface coverage is high and the binder evenly distributed. Although on the laboratory scale electrode formu-lations with a high binder content are common, they have little practical use in commercial devices due to the high content of inactive material. As the binder con-tent is decreased, complete surface coverage is more difficult to achieve and the binder distribution is more strongly coupled to the particle-binder interactions during the preparation process. Moreover, it is demonstrated in this thesis how these inter-actions are related to the surface area of the electrode components applied, the surface composition and the electrochemistry of the electrode. As a result of the smaller binder contents the benefits provided by CMC-Na and PAA at the electrode surface are compromised and the performance differs less distinctly from electrodes fabricated with the conventional binder, i.e. poly(vinylidene difluoride) (PVdF). Composites of alloying and conversion materials, on the other hand, typically em-ploy binders in larger amounts. Despite the frequently noted resiliency to volume expansion, which is also a positive side effect of the poor swellability of the binder in the electrolyte, the protection of the surface and the formation of a more stable interface are the major cause for the improved electrochemical behaviour, com-pared to electrodes employing PVdF binders.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2017. 84 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1490
Keyword
binder, CMC-Na, PAA, graphite, silicon, lithium-ion battery, photoelectron spectros-copy
National Category
Chemical Sciences
Research subject
Chemistry with specialization in Materials Chemistry; Chemistry with specialization in Polymer Chemistry; Chemistry with specialization in Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-317739 (URN)978-91-554-9855-9 (ISBN)
Public defence
2017-05-05, Ång/10132, Lägerhyddsvägen 1, Uppsala, 09:15 (English)
Opponent
Supervisors
Funder
Swedish Research Council
Available from: 2017-04-11 Created: 2017-03-17 Last updated: 2017-04-21

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Authority records BETA

Jeschull, FabianBrandell, DanielEdström, KristinaLacey, Matthew J.

Search in DiVA

By author/editor
Jeschull, FabianBrandell, DanielEdström, KristinaLacey, Matthew J.
By organisation
Structural Chemistry
In the same journal
Chemical Communications
Chemical Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
pubmed
urn-nbn

Altmetric score

doi
pubmed
urn-nbn
Total: 832 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf