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- Tammela, Petter, 1986-, et al.
(författare)
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Influence of Separator and Electrode Thickness on Cell Resistance in Energy Storage Devices based on Polypyrrole-Cellulose Composites
- 2014
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Ingår i: GradSAM21 workshop 2014.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The next-generation electronic industry requires access to inexpensive, flexible, light-weight and environmentally friendly energy storage devices [1]. Consequently, a lot of research has been directed toward producing versatile and flexible materials as a complement to the materials used in contemporary batteries and supercapacitors. Electroactive polymers represent an attractive alternative and electronically conducting polymers have hence received considerable interest as it is well-known that these materials can be used to manufacture all-polymer-based batteries and supercapacitors [2]. The performance of such energy storage devices is, however, ultimately limited by the resistance of the cell [3]. One important aspect is therefore to consider the cell resistance when optimizing the performance and cell design.Our recent activities have shown that a flexible and highly porous cellulose and polypyrrole composite, obtained by polymerizing pyrrole on cellulose from the Cladophora sp. algae, can be used as paper-based electrode materials and together with an aqueous salt solution form an environmentally friendly charge storage device [4, 5]. The cellulose-polypyrrole-based device proved to cycle for thousands of cycles without significant loss of capacity even at high charge and discharge rates.In the present work, the cell resistances of cellulose-polypyrrole-based charge storage devices are investigated, and the influence of electrode material and separator thickness are examined. The effect of absorption of electrolyte in the separator compared to bulk solutions of electrolyte, and the contact resistances between current collectors and the composite are discussed, as well as the possibilities of designing inexpensive all-organic energy storage devices with promising performance regarding cycling stability, rate capability and cell resistance.
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| 3. |
- Tammela, Petter, 1986-, et al.
(författare)
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Influence of Separator and Electrode Thickness on Cell Resistance in Energy Storage Devices based on Polypyrrole-Cellulose Composites
- 2014
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Ingår i: MRS Spring meeting April 21-25, 2014 - San Francisco, California.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- At present there is a strong need for the development of inexpensive, flexible, light-weight and environmentally friendly energy storage devices [1]. In this process, research is carried out to develop new versatile and flexible electrode materials as a complement to the materials used in contemporary batteries and supercapacitors. These activities have resulted in an increased interest in electronically conducting polymers (e.g. polyaniline, polypyrrole, and polythiophene) as it is known since more than two decades [2, 3] that these materials can be used to manufacture all-polymer-based batteries and supercapacitors. However, the latter devices generally suffer from problems due to low capacities, slow charging rates, poor cycling stabilities and high self-discharge rates [2]. Possible approaches to circumvent at least some of these problems involve the use of conducting polymers with carbon nanotubes [4] or cellulose [5].We have recently shown [5], that flexible composites, made of cellulose and polypyrrole, by chemical polymerization of pyrrole on a cellulose substrate derived from the Cladophora sp. algae, can be used as paper-based electrode materials for environmental friendly charge storage devices. The device, which has been referred to as the “Salt and Paper Battery” [6], was found to exhibit good cycling stability even at high charging and discharging rates. The latter results open up to exciting possibilities for the development of green and foldable devices as well as for a range of new applications, incompatible with conventional batteries and supercapacitors.The poster will focus on the results of our recent and ongoing research concerning polypyrrole and cellulose composite charge storage devices. It will be shown how the total cell resistances in the devices are influenced by thickness of the polypyrrole and cellulose composite, the thickness of the separator, and additives in the composite. Furthermore, the influence of the porosity of the separator, and the contact resistances between current collectors and the composite will be briefly discussed. It will be shown that a cheap all organic energy storage device can be assembled with promising performance.
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| 4. |
- Tammela, Petter, et al.
(författare)
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The influence of electrode and separator thickness on the cell resistance of symmetric cellulose–polypyrrole-based electric energy storage devices
- 2014
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 272, s. 468-475
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Tidskriftsartikel (refereegranskat)abstract
- The influence of the cell design of symmetric polypyrrole and cellulose-based electric energy storage devices on the cell resistance was investigated using chronopotentiometric and ac impedance measurements with different separator and electrode thicknesses. The cell resistance was found to be dominated by the electrolyte and current collector resistances while the contribution from the composite electrode material was negligible. Due to the electrolyte within the porous electrodes thin separators could be used in combination with thick composite electrodes without loss of performance. The paper separator contributed with a resistance of similar to 1.5 Omega mm(-1) in a 1.0 M NaNO3 electrolyte and the tortuosity value for the separator was about 2.5. The contribution from the graphite foil current collectors was about similar to 0.4-1.1 Omega and this contribution could not be reduced by using platinum foil current collectors due to larger contact resistances. The introduction of chopped carbon fibres into the electrode material or the application of pressure across the cells, however, decreased the charge transfer resistance significantly. As the present results demonstrate that cells with higher charge storage capacities but with the same cell resistance can be obtained by increasing the electrode thickness, the development of paper based energy storage devices is facilitated.
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