Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • 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
Exploration of Non-Aqueous Metal-O2 Batteries via In Operando X-ray Diffraction
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. (Ångström Advanced Battery Center)ORCID iD: 0000-0002-8915-3032
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Description
Abstract [en]

Non-aqueous metal-air (Li-O2 and Na-O2) batteries have been emerging as one of the most promising high-energy storage systems to meet the requirements for demanding applications due to their high theoretical specific energy. In the present thesis work, advanced characterization techniques are demonstrated for the exploration of metal-O2 batteries. Prominently, the electrochemical reactions occurring within the Li-O2 and Na-O2 batteries upon cycling are studied by in operando powder X-ray diffraction (XRD).

In the first part, a new in operando cell with a combined form of coin cell and pouch cell is designed. In operando synchrotron radiation powder X-ray diffraction (SR-PXD) is applied to investigate the evolution of Li2O2 inside the Li-O2 cells with carbon and Ru-TiC cathodes. By quantitatively tracking the Li2O2 evolution, a two-step process during growth and oxidation is observed.

This newly developed analysis technique is further applied to the Na-O2 battery system. The formation of NaO2 and the influence of the electrolyte salt are followed quantitatively by in operando SR-PXD. The results indicate that the discharge capacity of Na-O2 cells containing a weak solvating ether solvent depends heavily on the choice of the conducting salt anion, which also has impact on the growth of NaO2 particles.

In addition, the stability of the discharge product in Na-O2 cells is studied. Using both ex situ and in operando XRD, the influence of sodium anode, solvent, salt and oxygen on the stability of NaO2 are quantitatively identified. These findings bring new insights into the understanding of conflicting observations of different discharge products in previous studies.

In the last part, a binder-free graphene based cathode concept is developed for Li-O2 cells. The formation of discharge products and their decomposition upon charge, as well as different morphologies of the discharge products on the electrode, are demonstrated. Moreover, considering the instability of carbon based cathode materials, a new type of titanium carbide on carbon cloth cathode is designed and fabricated. With a surface modification by loading Ru nanoparticles, the titanium carbide shows enhanced oxygen reduction/evolution activity and stability. Compared with the carbon based cathode materials, titanium carbide demonstrated a higher discharge and charge efficiency.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2017. , 71 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1572
Keyword [en]
Keywords: lithium-oxygen batteries, sodium-oxygen batteries, metal-air, in operando X-ray diffraction, cathode materials
National Category
Materials Chemistry
Research subject
Chemistry with specialization in Materials Chemistry
Identifiers
URN: urn:nbn:se:uu:diva-330889ISBN: 978-91-513-0094-8 (print)OAI: oai:DiVA.org:uu-330889DiVA: diva2:1147475
Public defence
2017-11-24, ITC 1211, Lägerhyddsvägen 2, Uppsala, 09:15 (English)
Opponent
Supervisors
Available from: 2017-11-02 Created: 2017-10-06 Last updated: 2017-11-02
List of papers
1. Towards an Understanding of Li2O2 Evolution in Li–O2Batteries: An In Operando Synchrotron X-ray DiffractionStudy
Open this publication in new window or tab >>Towards an Understanding of Li2O2 Evolution in Li–O2Batteries: An In Operando Synchrotron X-ray DiffractionStudy
Show others...
2017 (English)In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, 1592-1599 p.Article in journal (Other academic) Published
National Category
Chemical Sciences Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-330768 (URN)10.1002/cssc.201601718 (DOI)
Projects
Li-air batteries
Available from: 2017-10-03 Created: 2017-10-03 Last updated: 2017-10-06
2. Free Standing Ru-TiC Nanowire Array/Carbon Textile Cathode with Enhanced Stability for Li-O2 Batteries
Open this publication in new window or tab >>Free Standing Ru-TiC Nanowire Array/Carbon Textile Cathode with Enhanced Stability for Li-O2 Batteries
Show others...
(English)Manuscript (preprint) (Other academic)
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-330773 (URN)
Projects
Li-air batteries
Available from: 2017-10-03 Created: 2017-10-03 Last updated: 2017-10-06
3. Growth of NaO2 in Highly Efficient Na–O2 Batteries Revealed by Synchrotron In Operando X-ray Diffraction
Open this publication in new window or tab >>Growth of NaO2 in Highly Efficient Na–O2 Batteries Revealed by Synchrotron In Operando X-ray Diffraction
Show others...
2017 (English)In: ACS Energy Letters, E-ISSN 2380-8195, Vol. 2, 2440-2444 p.Article in journal, News item (Other academic) Published
National Category
Natural Sciences
Research subject
Chemistry with specialization in Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-330766 (URN)10.1021/acsenergylett.7b00768 (DOI)
Projects
Na-air batteries
Available from: 2017-10-03 Created: 2017-10-03 Last updated: 2017-10-18Bibliographically approved
4. Insights into the Stability of Discharge Products in Na-O2 Batteries
Open this publication in new window or tab >>Insights into the Stability of Discharge Products in Na-O2 Batteries
Show others...
(English)Manuscript (preprint) (Other academic)
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-330776 (URN)
Projects
Na-air batteries
Available from: 2017-10-03 Created: 2017-10-03 Last updated: 2017-10-11
5. 3-D binder-free graphene foam as cathode for high capacity Li-O2 batteries
Open this publication in new window or tab >>3-D binder-free graphene foam as cathode for high capacity Li-O2 batteries
Show others...
2016 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 4, no 25, 9767-9773 p.Article in journal (Other (popular science, discussion, etc.)) Published
Abstract [en]

To provide energy densities higher than those of conventional Li-ion batteries, a Li–O2 battery requires a cathode with high surface area to host large amounts of discharge product Li2O2. Therefore, reversible formation of discharge products needs to be investigated in Li–O2 cells containing high surface area cathodes. In this study, a binder-free oxygen electrode consisting of a 3-D graphene structure on aluminum foam, with a high defect level (ID/IG = 1.38), was directly used as the oxygen electrode in Li– O2 batteries, delivering a high capacity of about 9 *104 mA h g-1 (based on the weight of graphene) at the first full discharge using a current density of 100 mA ggraphene-1 . This performance is attributed to the 3-D porous structure of graphene foam providing both an abundance of available space for the deposition of discharge products and a high density of reactive sites for Li–O2 reactions. Furthermore, the formation of discharge products with different morphologies and their decomposition upon charge were observed by SEM. Some nanoscaled LiOH particles embedded in the toroidal Li2O2 were detected by XRD and visualized by TEM. The amount of Li2O2 formed at the end of discharge was revealed by a titration method combined with UV-Vis spectroscopy analysis. 

National Category
Materials Chemistry
Research subject
Chemistry with specialization in Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-291383 (URN)10.1039/C5TA10690G (DOI)000378716900008 ()
Conference
Inorganic Days, Visby, June 15 - 17, 2015
Projects
Swedish Research CouncilSwedish Energy AgencyÅngpanneföreningen’s Foundation for Research and DevelopmentJ. Gust. Richert FoundationState Key Laboratory of Fine Chemicals (KF1413)China Scholarship Council
Funder
Swedish Research Council, 2012-4681; 2011-6512Swedish Energy AgencyÅForsk (Ångpanneföreningen's Foundation for Research and Development)
Available from: 2016-05-02 Created: 2016-05-02 Last updated: 2017-10-06Bibliographically approved
6. Ink-jet printed highly conductive pristine graphene patterns achieved with water-based ink and aqueous doping processing
Open this publication in new window or tab >>Ink-jet printed highly conductive pristine graphene patterns achieved with water-based ink and aqueous doping processing
Show others...
2017 (English)In: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 114, 77-83 p.Article in journal (Refereed) Published
Abstract [en]

We report an efficient inkjet printing of water-based pristine GNPs graphene ink and a facile aqueous halogen doping process that provides significant and thermally stable conductivity enhancement of printed patterns. Highly concentrated aqueous graphene ink populated by few-layer pristine graphene flakes is obtained by means of scalable shear exfoliation process with the aid of bromine intercalation. The as-printed GNP films which has been merely treated by drying at 100 degrees C exhibits DC conductivity (sigma(DC)) of similar to 1400 S/m likely due to bromine doping effect. This value is significantly increased to similar to 3 x 10(4) S/m when an additional treatment by means of dipping in aqueous iodine solution is applied prior to the drying. As contrast, sigma(DC) is increased to similar to 2.4 x 10(4) S/m when a mere annealing at elevated temperature in air is employed. When the aqueous iodine doping process and annealing at elevated temperature is combined, an unprecedented value of sigma(DC) similar to 10(5) S/m is achieved. The availability of water-based GNPs inks and low-temperature doping scheme for efficient and reliable conductivity enhancement has offered a pathway for the application of GNPs in different printed electronics devices.

National Category
Materials Chemistry Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-317574 (URN)10.1016/j.carbon.2016.12.003 (DOI)000393249600010 ()
Funder
Swedish Foundation for Strategic Research , Dnr SE13-0061
Available from: 2017-03-22 Created: 2017-03-22 Last updated: 2017-10-06Bibliographically approved
7. Constraining Si Particles within Graphene Foam Monolith: Interfacial Modification for High-Performance Li+ Storage and Flexible Integrated Configuration
Open this publication in new window or tab >>Constraining Si Particles within Graphene Foam Monolith: Interfacial Modification for High-Performance Li+ Storage and Flexible Integrated Configuration
Show others...
2016 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 26, no 37, 6797-6806 p.Article in journal (Refereed) Published
Abstract [en]

Pulverization of electrode materials and loss of electrical contact have been identified as the major causes for the performance deterioration of alloy anodes in Li-ion batteries. This study presents the hierarchical arrangement of spatially confining silicon nanoparticles (Si NPs) within graphene foam (GF) for alleviating these issues. Through a freeze-drying method, the highly oriented GF monolith is engineered to fully encapsulate the Si NPs, serving not only as a robust framework with the well-accessible thoroughfares for electrolyte percolation but also a physical blocking layer to restrain Si from direct exposure to the electrolyte. In return, the pillar effect of Si NPs prevents the graphene sheets from restacking while preserving the highly efficient electron/Li+ transport channels. When evaluated as a binder-free anode, impressive cycle performance is realized in both half-cell and full-cell configurations. Operando X-ray diffraction and in-house X-ray photoelectron spectroscopy confirm the pivotal protection of GF to sheathe the most volume-expanded lithiated phase (Li15Si4) at room temperature. Furthermore, a free-standing composite film is developed through readjusting the pore size in GF/Si monolith and directly integrated with nanocellulose membrane (NCM) separator. Because of the good electrical conductivity and structural integrity of the GF monolith as well as the flexibility of the NCM separator, the as-developed GF/Si-NCM electrode showcases the potential use in the flexible electronic devices.

National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-306736 (URN)10.1002/adfm.201602324 (DOI)000384810300011 ()
Funder
Swedish Foundation for Strategic Research Swedish Research Council, 2012-4681StandUpSwedish Energy Agency
Available from: 2016-11-10 Created: 2016-11-03 Last updated: 2017-10-06Bibliographically approved
8. Encasing Si particles within a versatile TiO2−xFx layer as an extremely reversible anode for high energy-density lithium-ion battery
Open this publication in new window or tab >>Encasing Si particles within a versatile TiO2−xFx layer as an extremely reversible anode for high energy-density lithium-ion battery
Show others...
2016 (English)In: Nano Energy, ISSN 2211-2855, Vol. 30, 745-755 p.Article in journal (Refereed) Published
Abstract [en]

The chemical phenomena occurring at the electrode-electrolyte interfaces profoundly determine the cycle behavior of a lithium ion battery. In this work, we report that silicon-based anodes can attain enhanced levels of capacity retention, rate performance and lifespan when a versatile protective layer of, F-doped anatase (TiO2−xFx), is applied towards taming the interfacial chemistry of the silicon particles. With careful choice of titanium fluoride as a precursor, internal voids can be generated upon in-situ fluoride etching of the native oxide layer and are used to alleviate the mechanical stress caused by volume expansion of silicon during cycling. In the course of F-doping, part of the Ti4+(d0) ions in anatase are reduced to Ti3+(d1), thereby increasing charge carriers in the crystal structure. Hence, the multifunctional F-doped TiO2−x coating, not only minimizes the direct exposure of the Si surface to the electrolyte, but also improves the electronic conductivity via inter-valence electron hopping. The best-performing composite electrode, Si@TiO2−xFx-3, delivered a satisfactory performance in both half-cell and full-cell configurations. Furthermore, we present a study of 1) the Si valence change at the buried interface using synchrotron based hard X-ray photoelectron spectroscopy, and 2) the phase transformation of the electrode monitored in operando using X-ray diffraction. Based on these characterizations, we observe that the Li+ conducting intermediate phase (LixTiO2−xFx) formed inside the surface coating enables deep lithiation and delithiation of the silicon during battery operation, and thus increase the capacity that can be accessed from the electrodes.

Keyword
Si anode, Versatile interfacial layer, Operando X-ray Diffraction, Kinetic activation, High energy-density
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-311358 (URN)10.1016/j.nanoen.2016.09.026 (DOI)000390636100085 ()
Funder
Swedish Foundation for Strategic Research Swedish Research Council, 2012-4681StandUpSwedish Energy AgencyKnut and Alice Wallenberg Foundation
Note

The second and third author contributed equally to this work

Available from: 2016-12-24 Created: 2016-12-24 Last updated: 2017-10-06Bibliographically approved

Open Access in DiVA

fulltext(3032 kB)85 downloads
File information
File name FULLTEXT01.pdfFile size 3032 kBChecksum SHA-512
e9e75314e645b0e925485c0fa299c0eed766f7bc58617f6cd92549186d9aa132b73d155139635920879c0f53ab9e69a504c2ba9337f6dd90d0eb4665ba0752f4
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Liu, Chenjuan
By organisation
Structural Chemistry
Materials Chemistry

Search outside of DiVA

GoogleGoogle Scholar
Total: 85 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 671 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • 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