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- Kizling, Michal, et al.
(författare)
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Bioelectrodes based on pseudocapacitive cellulose/polypyrrole composite improve performance of biofuel cell
- 2016
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Ingår i: Bioelectrochemistry. - : Elsevier BV. - 1567-5394 .- 1878-562X. ; 112, s. 184-190
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Tidskriftsartikel (refereegranskat)abstract
- Enzymatic electrodes with high internal capacitance, based on cellulose/polypyrrole composite were optimized and utilized to design improved enzymatic fuel cell. Fructose dehydrogenase Gluconobacter sp. specifically adsorbed on the cellulose/polypyrrole matrix and electrophoretically immobilized and electrochemically entrapped Laccase Trametes versicolor, were used as the anode and cathode bioelectrocatalysts, respectively. The cellulose/polypyrrole composite film exhibited pseudocapacitive properties under mild pH conditions. Following modification with carboxylic groups the composite material enabled highly efficient adsorption of enzyme and provided good electrical contact between the enzymatic active sites and the electrode surface. The modified cellulose/polypyrrole composite based electrode was used for the anode leading to mediatorless fructose oxidation giving large catalytic current density, 12.8 mA cm(-2). Laccase and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) as the mediator entrapped in the cellulose/polypyrrole composite film generated dioxygen reduction current density of 2 mA cm(-2). Application of pseudocapacitive matrix and decreasing the distance between electrodes to 1 mm lead to improvement of the biofuel cell power output and its regeneration ability. The power of the cell was found to increase by introduction of a preconditioning step during which the cell was kept at open circuit voltage under fuel flow. After 24 h of preconditioning the matrix was recharged and the device output reached the power, 2.1 mW cm(-2) and OCV, 0.59 V.
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- Kizling, Michal, et al.
(författare)
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Biosupercapacitors for powering oxygen sensing devices
- 2015
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Ingår i: Bioelectrochemistry. - : Elsevier BV. - 1567-5394 .- 1878-562X. ; 106, s. 34-40
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Tidskriftsartikel (refereegranskat)abstract
- A biofuel cell comprising electrodes based on supercapacitive materials - carbon nanotubes and nanocellulose/polypyrrole composite was utilized to power an oxygen biosensor. Laccase Trametes versicolor, immobilized on naphthylated multi walled carbon nanotubes, and fructose dehydrogenase, adsorbed on a porous polypyrrole matrix, were used as the cathode and anode bioelectrocatalysts, respectively. The nanomaterials employed as the supports for the enzymes increased the surface area of the electrodes and provide direct contact with the active sites of the enzymes. The anode modified with the conducting polymer layer exhibited significant pseudocapacitive properties providing superior performance also in the high energy mode, e.g., when switching on/off the powered device. Three air-fructose biofuel cells connected in a series converted chemical energy into electrical giving 2 mW power and open circuit potential of 2 V. The biofuel cell system was tested under various externally applied resistances and used as a powering unit for a laboratory designed two-electrode minipotentiostat and a laccase based sensor for oxygen sensing. Best results in terms of long time measurement of oxygen levels were obtained in the pulse mode -45 s for measurement and 15 min for self-recharging of the powering unit.
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- Kizling, Michal, et al.
(författare)
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Pseudocapacitive polypyrrole-nanocellulose composite for sugar-air enzymatic fuel cells
- 2015
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Ingår i: Electrochemistry communications. - : Elsevier BV. - 1388-2481 .- 1873-1902. ; 50, s. 55-59
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Tidskriftsartikel (refereegranskat)abstract
- Efficient, new combination of a bioelectrocatalytic and a pseudocapacitive cellulose-based composite material is reported. The anode comprising Gluconobacter sp. fructose dehydrogenase physically adsorbed on Cladophora sp. Algae nanocellulose/polypyrrole composite provides large catalytic oxidation currents due to large effective surface area of the composite material, and enables storing of the charge. Supercapacitor properties are useful for larger current demands e.g. during switching on-off the devices. Mediatorless catalytic oxidation current densities as high as 14 mA cm(-2) at potentials as negative as -0.17 V vs. Ag/AgCl constitute the best anode performance without using mediators reported to date. The fuel cell with GCE cathode covered with laccase adsorbed on naphthylated multiwalled carbon nanotubes, exhibits improved parameters: open circuit voltage of 0.76 V, and maximum power density 1.6 mW cm(-2).
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- Pan, Ruijun, et al.
(författare)
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Mesoporous Cladophora cellulose separators for lithium-ion batteries
- 2016
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 321, s. 185-192
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Tidskriftsartikel (refereegranskat)abstract
- Much effort is currently made to develop inexpensive and renewable materials which can replace the polyolefin microporous separators conventionally used in contemporary lithium-ion batteries. In the present work, it is demonstrated that mesoporous Cladophora cellulose (CC) separators constitute very promising alternatives based on their high crystallinity, good thermal stability and straightforward manufacturing. The CC separators, which are fabricated using an undemanding paper-making like process involving vacuum filtration, have a typical thickness of about 35 mu m, an average pore size of about 20 nm, a Young's modulus of 5.9 GPa and also exhibit an ionic conductivity of 0.4 mS cm(-1) after soaking with 1 M LiPF6 EC: DEC (1/1, v/v) electrolyte. The CC separators are demonstrated to be thermally stable at 150 degrees C and electrochemically inert in the potential range between 0 and 5 V vs. Li+/Li. A LiFePO4/Li cell containing a CC separator showed good cycling stability with 99.5% discharge capacity retention after 50 cycles at a rate of 0.2 C. These results indicate that the renewable CC separators are well-suited for use in high-performance lithium-ion batteries.
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