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The impact of size effects on the electrochemical behaviour of Cu2O-coated Cu nanopillars for advanced Li-ion microbatteries
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, Inorganic Chemistry.
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
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2014 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 2, no 25, 9574-9586 p.Article in journal (Refereed) Published
Abstract [en]

The generation of a distribution of nanoparticles upon conversion reaction of thin Cu2O layers is demonstrated to produce a wide electrochemical potential window, as well as a distinctive capacity increase in large area three-dimensional electrodes. Cu nanopillars with a 10-15 nm Cu2O coating containing traces of nanocrystattine Fe2O3 yield capacities up to 0.265 mA h cm(-2) (at 61 mA g(-1)), excellent cycling for more than 300 cycles and an electroactive potential window larger than 2 V. due to the size effects caused by the various Cu/Cu2O nanopartictes formed during conversion/deconversion. These 3D Li-ion battery electrodes based on etectrodeposited Cu nanopillars spontaneously coated with a Cu2O layer are compatible with current densities of 16 A g(-1) (i.e. 61 C rates) after aerosol-assisted infiltration with an iron acetate solution followed by low-temperature pyrolysis. The capacity of the composite material increases by 67% during 390 cycles due to the growth of the electroactive area during the electrochemical milling of Cu2O forced by its repeated conversion/de-conversion. The latter generates a distribution of nanoparticles with different sizes and redox potentials, which explains the broad potential window, as well as the significant capacity contribution from double layer charging. These 3D electrodes should be well-suited for Li-ion microbatteries and Li-ion batteries in general, since they combine high capacities per footprint area with excellent power capabilities. More importantly, such electrodes grant access to fundamental understanding of the electrochemical behaviour of these active materials providing new insights into both conversion mechanisms and nanostructured interfaces more in general.

Place, publisher, year, edition, pages
2014. Vol. 2, no 25, 9574-9586 p.
National Category
Other Chemistry Topics Other Physics Topics
URN: urn:nbn:se:uu:diva-228953DOI: 10.1039/c4ta01361aISI: 000337774100019OAI: oai:DiVA.org:uu-228953DiVA: diva2:735335
Available from: 2014-07-25 Created: 2014-07-24 Last updated: 2015-11-10
In thesis
1. Insights into Electrochemical Energy Storage by use of Nanostructured Electrodes
Open this publication in new window or tab >>Insights into Electrochemical Energy Storage by use of Nanostructured Electrodes
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Template-assisted electrodeposition is a powerful technique for fabricating complex nanostructured electrodes. Through the use of pulsed-electrodeposition nanostructured electrodes of Al, Cu and Sn have been realised and subsequently coated electrochemically with V2O5, MnxO, Li, Cu2O and a polymer electrolyte. Nanorods with a multi-layered Cu2O/Cu structure have likewise been produced through electrodeposition. Nanostructured electrodes are ideal for studying electrochemical energy storage and have as such been used to investigate the electrochemistry of conversion and alloying reactions in detail.

Key properties of the Cu2O conversion reaction were found to be dependent on the particle size. Prolonged cycling was seen to induce an electrochemical milling process which reduced the particle size. This process was found to improve the cell capacity retention due to improved accessibility of the material. The redox potential at which the particles react was found to be size dependent as smaller particles reacted at lower potentials.

The Li-alloying reaction was also investigated by analysing several different alloy-forming materials. All materials exhibited a decline in capacity during cell cycling. This decline was observed to be time dependent and could as such be explained by a diffusion limited process. Moreover, the capacity losses were found to occur during partial lithiation of the electrode material leading to Li trapping in the electrode material. Li trapping was also observed for commonly used anode current collectors as the metals have some solubility for Li. Conducting boron-doped diamond electrodes were however seen to be resistant to Li diffusion and are therefore recommended as viable current collectors for anodes handling metallic lithium (i.e. Li-alloys and Li metal).

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2015. 79 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1297
National Category
Inorganic Chemistry
Research subject
Chemistry with specialization in Inorganic Chemistry
urn:nbn:se:uu:diva-263482 (URN)978-91-554-9352-3 (ISBN)
Public defence
2015-11-20, Häggsalen, Ångströmslaboratoriet, Lägerhyddsvägen 1, Uppsala, 09:15 (English)
Available from: 2015-10-28 Created: 2015-09-30 Last updated: 2015-11-10

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Valvo, MarioRehnlund, DavidHahlin, MariaEdström, KristinaNyholm, Leif
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