| 1. |
- Karlsson, Christoffer, et al.
(författare)
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Stable Deep Doping of Vapor-Phase Polymerized Poly(3,4-ethylenedioxythiophene)/Ionic Liquid Supercapacitors.
- 2016
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 9:16, s. 2112-2121
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Tidskriftsartikel (refereegranskat)abstract
- Liquid-solution polymerization and vapor-phase polymerization (VPP) have been used to manufacture a series of chloride- and tosylate-doped poly(3,4-ethylenedioxythiophene) (PEDOT) carbon paper electrodes. The electrochemistry, specific capacitance, and specific charge were determined for single electrodes in 1-ethyl-3-methylimidazolium dicyanamide (emim dca) ionic liquid electrolyte. VPP-PEDOT exhibits outstanding properties with a specific capacitance higher than 300 F g(-1) , the highest value reported for a PEDOT-based conducting polymer, and doping levels as high as 0.7 charges per monomer were achieved. Furthermore, symmetric PEDOT supercapacitor cells with the emim dca electrolyte exhibited a high specific capacitance (76.4 F g(-1) ) and high specific energy (19.8 Wh kg(-1) ). A Ragone plot shows that the VPP-PEDOT cells combine the high specific power of conventional ("pure") capacitors with the high specific energy of batteries, a highly sought-after target for energy storage.
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| 2. |
- Keskinen, Jari, et al.
(författare)
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Asymmetric and symmetric supercapacitors based on polypyrrole and activated carbon electrodes
- 2015
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Ingår i: Synthetic metals. - : Elsevier BV. - 0379-6779 .- 1879-3290. ; 203, s. 192-199
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Supercapacitors were prepared using either two polypyrrole (PPy) composite electrodes or one PPy composite and one activated carbon electrode. The PPy composite electrodes were either freestanding paper-like sheets or PPy films printed on graphite ink coated aluminium/PET laminate substrates, using Cladophora algae derived cellulose as the substrate or binder, respectively. The specific capacitance of the PPy electrodes was found to be about 200 F g−1 depending on the manufacturing method, yielding supercapacitors with capacitances between 0.45 and 3.8 F and energy efficiencies of over 90%. For an asymmetric device with activated carbon positive electrode and PPy negative electrode a capacitance loss of 5% was seen after 14300 cycles.
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| 3. |
- Araujo, Rafael B., et al.
(författare)
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Assessing Electrochemical Properties of Polypyridine and Polythiophene for Prospective Application in Sustainable Organic Batteries
- 2017
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - 1463-9076 .- 1463-9084. ; 19:4, s. 3307-3314
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Tidskriftsartikel (refereegranskat)abstract
- Conducting polymers are being considered promising candidates for sustainable organic batteries mainly due to their fast electron transport properties and high recyclability. In this work, key properties of polythiophene and polypyridine have been assessed through a combined theoretical and experimental study focusing on such applications. A theoretical protocol has been developed to calculate redox potentials in solution within the framework of the density functional theory and using continuous solvation models. Here, the evolution of the electrochemical properties of solvated oligomers as a function of the length of the chain is analyzed and then the polymer properties are estimated via linear regressions using ordinary least square. The predicted values were verified against our electrochemical experiments. This protocol can now be employed to screen a large database of compounds in order to identify organic electrodes with superior properties.
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| 4. |
- Araujo, Rafael B., et al.
(författare)
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Designing strategies to tune reduction potential of organic molecules for sustainable high capacity batteries application
- 2017
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Ingår i: Journal of Materials Chemistry A. - 2050-7488 .- 2050-7496. ; 5:9, s. 4430-4454
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Tidskriftsartikel (refereegranskat)abstract
- Organic compounds evolve as a promising alternative to the currently used inorganic materials in rechargeable batteries due to their low-cost, environmentally friendliness and flexibility. One of the strategies to reach acceptable energy densities and to deal with the high solubility of known organic compounds is to combine small redox active molecules, acting as capacity carrying centres, with conducting polymers. Following this strategy, it is important to achieve redox matching between the chosen molecule and the polymer backbone. Here, a synergetic approach combining theory and experiment has been employed to investigate this strategy. The framework of density functional theory connected with the reaction field method has been applied to predict the formal potential of 137 molecules and identify promising candidates for the referent application. The effects of including different ring types, e.g. fused rings or bonded rings, heteroatoms, [small pi] bonds, as well as carboxyl groups on the formal potential, has been rationalized. Finally, we have identified a number of molecules with acceptable theoretical capacities that show redox matching with thiophene-based conducting polymers which, hence, are suggested as pendent groups for the development of conducting redox polymer based electrode materials.
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| 5. |
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| 6. |
- Byström, Anna, et al.
(författare)
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Lateral movement of the saddle relative to the equine spine in rising and sitting trot on a treadmill
- 2018
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Saddle slip, defined as a progressive lateral displacement of the saddle during ridden exercise, has recently been given attention in the scientific press as a potential sign of lameness. The aim of this study was to objectively quantify the normal lateral movement (oscillations) of the saddle relative to the horse in non-lame horses, and associate this movement to the movements of the horse and rider. Data from seven Warmblood dressage horses competing at Grand Prix (n = 6) or FEI Intermediate (n = 1) level, ridden by their usual riders, were used. Simultaneous kinetic, kinematic and saddle pressure measurements were conducted during sitting and rising trot on a force-measuring treadmill. The maximum lateral movement of the caudal part of the saddle relative to the horse's spine (MAX) was determined for each diagonal step. A mixed model was applied, with MAX as outcome, and T6 and S3 vertical position, rigid body rotation angles (roll, pitch, yaw) of the horse's and rider's pelvis, vertical ground reaction forces, saddle force, and rider position (rising in rising trot, sitting in rising trot or sitting in sitting trot) as explanatory variables. The least square means for MAX were 14.3 (SE 4.7) mm and 23.9 (SE 4.7) mm for rising and sitting in rising trot, and 20.3 (SE 4.7) mm for sitting trot. A 10 mm increase in maximum pelvic height at push off increased MAX by 1.4 mm (p<0.0001). One degree increase in rider pelvis roll decreased MAX 1.1 mm, and one degree increase in rider pelvis yaw increased MAX 0.7 mm (both p<0.0001). The linear relationships found between MAX and movements of both horse and rider implies that both horse and rider movement asymmetries are reflected in the lateral movements or oscillations of the saddle in non-lame horses.
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| 7. |
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| 8. |
- Emanuelsson, Rikard, et al.
(författare)
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An All-Organic Proton Battery
- 2017
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 139:13, s. 4828-4834
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Tidskriftsartikel (refereegranskat)abstract
- Rechargeable batteries that use organic matter as. the capacity-carrying material have previously been considered a technology for the future. Earlier batteries in which both the anode and cathode consisted of organic material required significant amounts of conductive additives and were often based on metal-ion electrolytes containing Li+ or Na+. However, we have used conducting poly(3,4-ethylenedioxythiophene) (PEDOT), functionalized with anthraquinone (PEDQT-AQ) or, benzonquinone (PEDOT-BQ) pendant groups as the negative and positive electrode materials, respectively, to make an all-organic proton battery devoid of metals. The electrolyte consists of a proton donor and acceptor slurry containing substituted pyridinium triflates and the corresponding pyridine base. This slurry allows the 2e(-)/2H(+) quinone/hydroquinone redox reactions while suppressing proton reduction in the battery cell. By using strong (acidic) proton donors, the formal potential of the quinone redox reactions is tuned into the potential region in which the PEDOT backbone is conductive, thus eliminating the need for conducting additives. In this all-organic proton battery cell, PEDOT-AQ and PEDOT-BQ deliver 103 and 120 mAh g(-1), which correspond to 78% and 75%, respectively, of the theoretical specific capacity of the materials at an average cell potential of 0.5 V. We show that PEDOT-BQ determines the cycling stability of the device while PEDOT-AQ provides excellent reversibility for at least 1000 cycles. This proof-of-concept shows the feasibility of assembling all organic proton batteries which require no conductive additives and also reveals where the challenges and opportunities lie on the path to producing plastic batteries.
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| 9. |
- Emanuelsson, Rikard, et al.
(författare)
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Enthalpic versus Entropic Contribution to the Quinone Formal Potential in a Polypyrrole-Based Conducting Redox Polymer
- 2016
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 120:38, s. 21178-21183
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Tidskriftsartikel (refereegranskat)abstract
- A conducting redox polymer (CPR) based on pyrrole with a hydroquinone pendant group was synthesized through electropolymerization of the corresponding monomer. The formal potential (E-0') in aqueous solution at different pH as well as in MeCN containing equal amounts of pyridiniumtriflates and the corresponding free pyridine with different pK(a) was investigated. E-0' could be completely recovered in MeCN, and by utilizing pyridine bases with different donor acceptor strengths, a decrease of 61 meV/pK(a) was found that corresponded exactly to the pH dependence of E-0' in aqueous electrolyte. To separate the entropic and enthalpic contributions to E-0', temperature-dependent electrochemistry was performed. Two different modes of operation with changing pH/pK(a) between the two media were revealed. In MeCN, E-0' varies only because of the enthalpic contribution as the entropic contribution is unaffected by change in pKa. In water, there is primarily an entropic contribution to E-0' with changing pH due to solvation of the proton. The presented results are expected to open up for new design possibilities of CRPs based on ion coordinating redox groups for electrical energy storage.
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| 10. |
- Emanuelsson, Rikard, et al.
(författare)
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Quinone based conducting redox polymers for electrical energy storage
- 2017
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Ingår i: Russian journal of electrochemistry. - : MAIK NAUKA/INTERPERIODICA/SPRINGER. - 1023-1935 .- 1608-3342. ; 53:1, s. 8-15
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Tidskriftsartikel (refereegranskat)abstract
- Conducting redox polymers (CRPs) constitute a promising class of materials for the development of organic matter based batteries with the potential to overcome the main limitations connected to this type of rechargeable battery systems including low conductivity and dissolution problems. In this report we show that the potential of quinones can be effectively tuned into the conducting region of polypyrrole (PPy), both in water based solutions and in acetonitrile, which is a prerequisite for profitable combination of the two units. We also present a device where both anode and cathode are made from PPy substituted with different quinone pendant groups and where good rate performance is achieved without any conductivity additives thus providing support for the hypothesized synergetic effect of a conducting polymer backbone and a covalently attached redox active pendant group. This device constitutes, to the best of our knowledge, the first all-CRP based battery reported to date.
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