| 1. |
- Ahlström, Johan, et al.
(författare)
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Electrochemical properties of oxide scale on steel exposed in saturated calcium hydroxide solutions with or without chlorides
- 2018
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Ingår i: International Journal of Corrosion. - : Hindawi Limited. - 1687-9325 .- 1687-9333. ; 2018
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Tidskriftsartikel (refereegranskat)abstract
- The electrochemical properties of various iron oxide scales on steel exposed in saturated calcium hydroxide solutions were investigated. The iron oxide scales were manufactured by different heat treatments and grinding processes and characterized using X-ray diffraction and scanning electron microscope. The electrochemical properties of the scales were assessed by measuring the corrosion potential and using electrochemical impedance spectroscopy and potentiodynamic polarization curves. It was found that wustite and magnetite are less noble compared to hematite but are more effective as cathodic surfaces. The results show that the electrochemical properties of the mill scale can be an important contributing factor in the corrosion of steel in concrete.
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| 2. |
- Asp, Leif, 1966, et al.
(författare)
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Realisation of structural battery composite materials
- 2015
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Ingår i: ICCM International Conferences on Composite Materials. - : International Committee on Composite Materials.
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Konferensbidrag (refereegranskat)abstract
- This paper introduces the concept of structural battery composite materials and their possible devices and the rationale for developing them. The paper presents an overview of the research performed in Sweden on a novel structural battery composite material. The research areas addressed include: carbon fibre electrodes, structural separators, multifunctional matrix materials, device architectures and material functionalization. Material characterization, fabrication and validation are also discussed. The paper focuses on a patented battery composite material technology. Here, carbon fibres are employed as combined negative battery electrodes and reinforcement, coated with a solid polymer electrolyte working simultaneously as electrolyte and separator with ability to transfer mechanical loads. The coated fibres are distributed in a conductive positive cathode material on an aluminium electron collector film. Efficient Li-ion transport between the electrodes is achieved by the solid polymer electrolyte coating being only a few hundred nanometres thick. Finally some outstanding scientific and engineering challenges are discussed. Such challenges, calling for further research are related to manufacture, development of new solid polymer electrolytes for improved multifunctionality and the lack of material models.
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| 3. |
- Gatty, Hithesh Kumar, 1980-, et al.
(författare)
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A ppb level, miniaturized fast response amperometric nitric oxide sensor for asthma diagnostics
- 2013
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Ingår i: Micro Electro Mechanical Systems (MEMS), 2013 IEEE 26th International Conference on. - New York : IEEE. - 9781467356541 ; , s. 1001-1004
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Konferensbidrag (refereegranskat)abstract
- This paper reports on a novel miniaturized MEMS-based amperometric nitric oxide sensor that is suitable for a point of care testing device for asthma. The novelty lies in the combination of a high surface area microporous structured electrode, nano-structured Nafion that is coated on the side walls of the micropores, and liquid electrolyte. This combination allows detection of very low concentration (parts-per-billion) gas, has a high sensitivity of 4 mu A/ppm/cm(2) and has both a response and a recovery time of 6 s. The sensor is integrated with a PCB potentiostat to form a complete measuring module. The limit of detection of this sensor was estimated to be 0.3 ppb.
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| 4. |
- Gatty, Hithesh K., et al.
(författare)
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An amperometric nitric oxide sensor with fast response and ppb-level concentration detection relevant to asthma monitoring
- 2015
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 209, s. 639-644
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Tidskriftsartikel (refereegranskat)abstract
- A MEMS-based amperometric nitric oxide (NO) gas sensor is reported in this paper. The sensor is designed to detect NO gas for the purpose of asthma monitoring. The unique property of this sensor lies in the combination of a microporous high-surface area electrode that is coated with Nafion (TM), together with a liquid electrolyte. The sensor is able to detect gas concentrations of the order of parts-per-billion (ppb) and has a measured NO sensitivity of 0.045 nA/ppb and an operating range between 25 and 65% relative humidity. The settling time of the sensor is measured to 8s. The selectivity to interfering gases such as ammonia (NH3) and carbon monoxide (CO) was high when placing an activated carbon fiber filter above the sensor. The ppb-level detection capability of this sensor combined with its relatively fast response, high selectivity to CO and NH3 makes the sensor potentially applicable in gas monitoring for asthma detection.
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| 5. |
- Hagberg, Johan, et al.
(författare)
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High precision coulometry of commercial PAN-based carbon fibers as electrodes in structural batteries
- 2016
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Ingår i: Journal of the Electrochemical Society. - : Electrochemical Society Inc.. - 0013-4651 .- 1945-7111. ; 163:8, s. A1790-A1797
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Tidskriftsartikel (refereegranskat)abstract
- Carbon fibers have the combined mechanical and electrochemical properties needed to make them particularly well suited for usage as electrodes in a structural lithium-ion battery, amaterial that simultaneously works as a battery and a structural composite. Presented in this paper is an evaluation of commercial polyacrylonitrile-based carbon fibers in terms of capacity and coulombic efficiency, as well as a microstructural and surface evaluation. Some polyacrylonitrile based carbon fibers intercalate lithium ions, resulting in a similar capacity as state-of-the-art graphite based electrodes, presently the most commonly used negative electrode material. Using high precision coulometry, we found a capacity of around 250-350 mAh/g and a very high coulombic efficiency of over 99.9% after ten cycles, which is even higher than a commercial state-of-the art graphitic electrode evaluated as reference. The high coulombic efficiency is attributed to the very low surface area of the carbon fibers, resulting in a small and stable solid-electrolyte interface layer. A highly graphitized ultra high modulus carbon fiber was evaluated as well and, compared to the other fibers, less lithium was inserted (corresponding to approximately 150 mAh/g). We show that the use of carbon fibers as an electrode material in a structural composite battery is indeed viable.
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| 6. |
- Hassel, Beatriz I., et al.
(författare)
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A Study on the Morphology, Mechanical, and Electrical Performance of Polyaniline-modified Wood - A Semiconducting Composite Material
- 2014
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Ingår i: BioResources. - : BioResources. - 1930-2126. ; 9:3, s. 5007-5023
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the morphology, electrochemical modification with respect to the wood fiber direction, and mechanical properties of wood modified by in situ polymerization with polyaniline (PANI). This polymerization formed a composite material with applications as an antistatic, electromagnetic, anti-corrosion, and heavy metal purifying materials. The polymer was found throughout the entire structure of the wood and was quantified within the wood cell wall and middle lamella by SEM-EDX. The presence of PANI affected the conductivity of the composite specimens, which was found to be higher in the fiber direction, indicating a more intact percolation pathway of connected PANI particles in this direction. The PANI modification resulted in a small reduction of the storage modulus, the maximum strength, and the ductility of the wood, with decreases in the properties of specimens conditioned in an environment above 66% relative humidity. The in situ-polymerized PANI strongly interacted with the lignin component of the veneers, according to the decrease in the lignin glass transition temperature (T-g) noted in DMA studies.
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| 7. |
- Jacques, Eric, et al.
(författare)
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Piezo-Electrochemical Energy Harvesting with Lithium-Intercalating Carbon Fibers
- 2015
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society. - 1944-8244 .- 1944-8252. ; 7:25, s. 13898-13904
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Tidskriftsartikel (refereegranskat)abstract
- (Figure Presented) The mechanical and electrochemical properties are coupled through a piezo-electrochemical effect in Li-intercalated carbon fibers. It is demonstrated that this piezo-electrochemical effect makes it possible to harvest electrical energy from mechanical work. Continuous polyacrylonitrile-based carbon fibers that can work both as electrodes for Li-ion batteries and structural reinforcement for composites materials are used in this study. Applying a tensile force to carbon fiber bundles used as Li-intercalating electrodes results in a response of the electrode potential of a few millivolts which allows, at low current densities, lithiation at higher electrode potential than delithiation. More electrical energy is thereby released from the cell at discharge than provided at charge, harvesting energy from the mechanical work of the applied force. The measured harvested specific electrical power is in the order of 1 μW/g for current densities in the order of 1 mA/g, but this has a potential of being increased significantly.
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| 8. |
- Johannisson, Wilhelm, et al.
(författare)
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Analysis of carbon fiber composite electrode
- 2015
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Ingår i: ICCM International Conferences on Composite Materials. - : International Committee on Composite Materials.
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Konferensbidrag (refereegranskat)abstract
- In this article a novel energy-storing composite electrode is investigated with regards to its mechanical and electrochemical properties. This composite electrode consists of carbon fibers, which provide both the mechanical reinforcement and the negative electrode in the battery cell. Also, this carbon fiber composite electrode consists of a polymer matrix that can conduct lithium ions, in order to simultaneously act as the electrolyte in the battery cell. Electrochemical tests were performed on the manufactured composite electrode and show extremely promising results for the battery performance. Furthermore, mechanical tests show that the composite electrode has acceptable mechanical properties for structural use. It is shown that the internal distances in the composite are large, and volume fraction of fibers is low. This is not only significantly limiting the mechanical properties of the composite, but also the electrochemical properties. Overall, the carbon fiber composite electrode is found to have suitable characteristics for further research, where many further research topics are found in order to improve and characterize the composite further.
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| 9. |
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| 10. |
- Leijonmarck, Simon, et al.
(författare)
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Direct electropolymerization of polymer electrolytes onto carbon fibers - A route to structural batteries?
- 2014
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Ingår i: 16th European Conference on Composite Materials, ECCM 2014. - : European Conference on Composite Materials, ECCM. - 9780000000002
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Konferensbidrag (refereegranskat)abstract
- In an effort to further reduce weight of carbon fibre reinforced composites, the concept of structural batteries has arisen. A structural battery is a multifunctional material managing both energy storage and enabling of structural integrity. More specific, the carbon fibres in the composites are used as negative electrode in a Li-ion battery. A crucial part of such a battery is the preparation of a thin, ionically conductive and stiff polymer matrix. One route to realize this is the use of electropolymerization, which can cover each individual fibre with polymer. In this study, the surface morphology of coated carbon fibres is investigated with electron microscopy and atomic force microscopy. Additionally, the curing degree as a function of process temperature during polymerization is tested.
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