| 1. |
- Kim, Jae-Kwang, 1978, et al.
(author)
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Towards flexible secondary lithium batteries: polypyrrole-LiFePO4 thin electrodes with polymer electrolytes
- 2012
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In: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 1364-5501 .- 0959-9428. ; 22:30, s. 15045-15049
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Journal article (peer-reviewed)abstract
- A thin flexible polypyrrole-lithium iron phosphate (PPy-LiFePO4) based cathode has been fabricated. A slurry containing carbon black, a binder and the active material prepared by direct polymerization of pyrrole on the surface of LiFePO4 (LFP) was spread on an Al/carbon film substrate by the doctor blade method. Transmission electron micrographs reveal that PPy nanoparticles form a web like structure over the surface of LFP particles. After doping with lithium ions the PPy network becomes conducting. When evaluated as a cathode of 180 mu m thickness together with a gel polymer electrolyte and a lithium anode, the charge-discharge performance reveals that the electrochemical properties of LFP are influenced to a considerable extent by the PPy. The cells show high initial discharge capacities of 135 and 110 mA h g(-1) for 0.041 (C/10) and 0.21 (C/2) mA cm(-2), respectively, and high active material utilization. Furthermore the cells exhibit stable cycle properties even at 0.21 mA cm(-2) with a low capacity fade per cycle (similar to 0.3%).
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| 2. |
- Lim, D. H., et al.
(author)
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Polymer electrolytes based on poly(vinylidene fluoride-co-hexafluoropropylene) nanofibrous membranes containing polymer plasticizers for lithium batteries
- 2012
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In: Solid State Ionics. - : Elsevier BV. - 0167-2738. ; 225, s. 631-635
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Journal article (peer-reviewed)abstract
- Gel polymer electrolytes (GPEs) were prepared with electrospun poly(vinylidene fluoride-co-hexafluoropropylene) [P(VdF-HFP)] nanofibrous membrane containing low molecular-weight polymer plasticizers, poly(ethylene glycol) dimethyl ether (PEGDME, Mw = 250 and 500). The fibers of electrospun membrane were stacked in layers to give fully interconnected pore structure with high porosity. The porous structure acted as a good host matrix to accommodate the polymer plasticizers. Thermogravimetric analysis (TGA) and field emission scanning electron microscope (FE-SEM) were used for thermal and physical characterizations, respectively. The GPEs exhibit high electrolyte uptake, high ionic conductivity, high anodic stability, and low interfacial resistance. Ionic conductivity and electrolyte uptake increased with the decrease in molecular weight of the polymer plasticizer. Prototype cells using electrospun P(VdF-HFP) nanofibrous GPEs with polymer plasticizers showed stable cyclic performances at different C-rates.
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| 3. |
- Lim, Du Hyun, 1983, et al.
(author)
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Route to sustainable lithium-sulfur batteries with high practical capacity through a fluorine free polysulfide catholyte and self-standing Carbon Nanofiber membranes
- 2017
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 7:1, s. Article no. 6327 -
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Journal article (peer-reviewed)abstract
- We report on a new strategy to improve the capacity, reduce the manufacturing costs and increase the sustainability of Lithium-Sulfur (LiS) batteries. It is based on a semi-liquid cathode composed of a Li2S8 polysulphide catholyte and a binder-free carbon nanofiber membrane with tailored morphology. The polysulphides in the catholyte have the dual role of active material and providing Li+-conduction, i.e. no traditional Li-salt is used in this cell. The cell is able to deliver an areal capacity as high as 7 mAh cm(-2), twice than that of commercial Lithium-ion batteries (LiBs) and 2-4 times higher than that of state-of-the-art LiS cells. In addition, the battery concept has an improved sustainability from a material point of view by being mainly based on sulfur and carbon and being completely fluorine-free, no fluorinated salt or binders are used, and has potential for upscaling and competitive price. The combination of these properties makes the semi-liquid LiS cell here reported a very promising new concept for practical large-scale energy storage applications.
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| 4. |
- Manuel, J., et al.
(author)
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Electrochemical properties of lithium polymer batteries with doped polyaniline as cathode material
- 2012
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In: Materials Research Bulletin. - : Elsevier BV. - 0025-5408. ; 47:10, s. 2815-2818
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Conference paper (peer-reviewed)abstract
- Polyaniline (PAN!) was doped with different lithium salts such as LiPFG and LiClO4 and evaluated as cathode-active material for application in room-temperature lithium batteries. The doped PANT was characterized by FTIR and XPS measurements. In the FTIR spectra, the characteristic peaks of PANT are shifted to lower bands as a consequence of doping, and it is more shifted in the case of PANI doped with LiPFG. The cathodes prepared using PANT doped with LiPF6 and LiClO4 delivered initial discharge capacities of 125 mAh g(-1) and 112 mAh g(-1) and stable reversible capacities of 114 mAh g(-1) and 81 mAh g(-1), respectively, after 10 charge-discharge cycles. The cells were also tested using polymer electrolyte, which delivered highest discharge capacities of 142.6 mAh g(-1) and 140 mAh g(-1) and stable reversible capacities of 117 mAh g(-1) and 122 mAh g(-1) for PANT-LiPF6 and PANI-LiClO4, respectively, after 10 cycles. The cathode prepared with LiPFG doped PANT shows better cycling performance and stability as compared to the cathode prepared with LiClO4 doped PANT using both liquid and polymer electrolytes.
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