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Self-Supported Three-Dimensional Nanoelectrodes for Microbattery Applications
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry. (Ångström Advanced Battery and Fuel Cell Centre)
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry. (Ångström Advanced Battery and Fuel Cell Centre)
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
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2009 (English)In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 9, no 9, 3230-3233 p.Article in journal (Refereed) Published
Abstract [en]

A nanostructured three-dimensional (3D) microbattery has been produced and cycled in a Li-ion battery. It consists of a current collector of aluminum nanorods, a uniform layer of 17 nm TiO2 covering the nanorods made using ALD, an electrolyte and metallic lithium counter electrode. The battery is electrochemically cycled more than 50 times. The increase in total capacity is 10 times when using a 3D architechture compared to a 2D system for the same footprint area.

Place, publisher, year, edition, pages
American Chemical Society , 2009. Vol. 9, no 9, 3230-3233 p.
National Category
Chemical Sciences Engineering and Technology
Research subject
Inorganic Chemistry
Identifiers
URN: urn:nbn:se:uu:diva-119450DOI: 10.1021/nl9014843ISI: 000269654900025OAI: oai:DiVA.org:uu-119450DiVA: diva2:300240
Available from: 2010-02-25 Created: 2010-02-25 Last updated: 2017-12-12
In thesis
1. Nano-structured 3D Electrodes for Li-ion Micro-batteries
Open this publication in new window or tab >>Nano-structured 3D Electrodes for Li-ion Micro-batteries
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

A new challenging application for Li-ion battery has arisen from the rapid development of micro-electronics. Powering Micro-ElectroMechanical Systems (MEMS) such as autonomous smart-dust nodes using conventional Li-ion batteries is not possible. It is not only new batteries based on new materials but there is also a need of modifying the actual battery design. In this context, the conception of 3D nano-architectured Li-ion batteries is explored. There are several micro-battery concepts that are studied; however in this thesis, the focus is concentrated on one particular architecture that can be described as the successive deposition of battery components (active material, electrolyte, active material) on free-standing arrays of nano-sized columns of a current collector.

After a brief introduction about Li-ion batteries and 3D micro-batteries, the electrodeposition of Al through an alumina template using an ionic liquid electrolyte to form free-standing columns of Al current collector is described. The crucial deposition parameters influencing the nucleation and growth of the Al nano-rods are discussed.

The deposition of active electrode material on the nano-structured current collector columns is described for 2 distinct active materials deposited using different techniques.

Deposition of TiO2 using Atomic Layer Deposition (ALD) as active material on top of the nano-structured Al is also presented. The obtained deposits present high uniformity and high covering of the specific surface of the current collector. When cycled versus lithium and compared to planar electrodes, an increase of the capacity was proven to be directly proportional to the specific area gained from shifting from a 2D to a 3D construction.

Cu2Sb 3D electrodes were prepared by the electrodeposition of Sb onto a nano-structured Cu current collector followed by an annealing step forcing the alloying between the current collector and Sb. The volume expansion observed during Sb alloying with Li is buffered by the Cu matrix and thus the electrode stability is greatly enhanced (from only 20 cycles to more than 120 cycles).

Finally, the deposition of a hybrid polymer electrolyte onto the developed 3D electrodes is presented. Even though the deposition is not conformal and that issues of capacity fading need to be addressed, preliminary results attest that it is possible to cycle the obtained 3D electrode-electrolyte versus lithium without the appearance of short-circuits.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2010. 119 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 719
National Category
Atom and Molecular Physics and Optics
Research subject
Chemistry
Identifiers
urn:nbn:se:uu:diva-119485 (URN)978-91-554-7732-5 (ISBN)
Public defence
2010-04-01, Amphithéâtre Mattis, U1, Université Paul Sabatier, 31400 Toulouse, France, 10:00 (English)
Opponent
Supervisors
Available from: 2010-03-11 Created: 2010-02-25 Last updated: 2010-03-11Bibliographically approved
2. Synthesis and Characterisation of Ultra Thin Film Oxides for Energy Applications
Open this publication in new window or tab >>Synthesis and Characterisation of Ultra Thin Film Oxides for Energy Applications
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis describes studies of materials which can be exploited for hydrogen production from water and sunlight. The materials investigated are maghemite (γ-Fe2O3), magnetite (Fe3O4) and especially hematite (α-Fe2O3), which is an iron oxide with most promising properties in this field. Hematite has been deposited using Atomic Layer Deposition (ALD) - a thin-film technique facilitating layer-by-layer growth with excellent thickness control and step coverage. The iron oxides were deposited using bis-cyclopentadienyl iron (Fe(Cp)2) or iron pentacarbonyl (Fe(CO)5) in combination with an O2 precursor. Since it is crucial to have good control of the deposition process, the influence of substrate, process temperature, precursor and carrier gas have been investigated systematically. By careful control of these deposition parameters, three polymorphs of iron oxide could be deposited: hematite (α-Fe2O3), maghemite (γ-Fe2O3) and magnetite (Fe3O4).

The deposited materials were characterized using X-ray Diffraction, Raman and UV-VIS Spectroscopy, and Scanning Electron Microscopy. Hard X-ray Photoelectron Spectroscopy (HAXPES) was also used, since it is a non-destructive, chemically specific, surface sensitive technique – the surface sensitivity resulting from the short mean escape depth of the photoelectrons. The depth probed can be controlled by varying the excitation energy; higher photoelectron energies increasing the inelastic mean-free-path in the material.

HAXPES studies of atomic diffusion from F-doped SnO2 substrates showed increased doping levels of Sn, Si and F in the deposited films. Diffusion from the substrate was detected at annealing temperatures between 550 °C and 800 °C. Films annealed in air exhibited improved photocatalytic behavior; a photocurrent of 0.23 mA/cm2 was observed for those films, while the as-deposited hematite films showed no photo-activity whatsoever.

The optical properties of low-dimensional hematite were studied in a series of ultra-thin films (thicknesses in the 2-70 nm range). The absorption maxima were shifted to higher energies for films thinner than 20 nm, revealing a different electronic structure in thin films.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2014. 113 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1186
Keyword
Atomic Layer Deposition, Iron oxides, Hematite, Solar Water Splitting, Hard X-Ray Photoelectron Spectroscopy
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-232948 (URN)978-91-554-9048-5 (ISBN)
Public defence
2014-11-21, Polhemsalen, 10134, Ångström, Lägerhyddsvägen 1, Uppsala, 10:15 (English)
Opponent
Supervisors
Available from: 2014-10-30 Created: 2014-09-28 Last updated: 2015-01-23

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Publisher's full texthttp://pubs.acs.org/doi/abs/10.1021/nl9014843

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Perre, EmilieFondell, MattisNyholm, LeifLu, Jun

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