| 1. |
- Amin, Muhammad, 1979, et al.
(författare)
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Coin-cell Supercapacitors Based on CVD Grown and Vertically Aligned Carbon Nanofibers (VACNFs)
- 2017
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Ingår i: International Journal of Electrochemical Science. - : Elsevier BV. - 1452-3981. ; 12:7, s. 6653-6661
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Tidskriftsartikel (refereegranskat)abstract
- Complete supercapacitors (SCs) comprising vertically aligned carbon nanofibers (VACNFs) as electrode materials have been assembled as coin-cells. The VACNFs were grown directly onto the current collector by direct current plasma enhanced chemical vapor deposition (DC-PECVD), thereby providing excellent contact with the current collector, but also eliminating the need of any binder. The vertical alignment facilitates fast ion transport and the electrolyte to access the entire surface of the CNFs. The morphology of the VACNFs was evaluated by scanning electron microscopy (SEM), while the performance was assessed by several methods: cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and device related cycling by galvanostatic charge/discharge. The capacitance, 3.64 mF/cm2 , is >15 times higher than the capacitance of a coin-cell without CNFs and the cyclic performance shows these proof-of-concept SCs to retain >80% of the capacitance after 2000 full charge/discharge cycles. The direct growth of VACNFs as electrodes at the current collector opens pathways for SC production using existing coin-cell battery production technology.
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| 2. |
- Plylahan, Nareerat, 1984, et al.
(författare)
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Ionic liquid and hybrid ionic liquid/organic electrolytes for high temperature lithium-ion battery application
- 2016
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Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686. ; 216, s. 24-34
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Tidskriftsartikel (refereegranskat)abstract
- Ionic liquid (IL) and hybrid IL/organic electrolytes with pyrrolidinium cation based ILs have been investigated for application in high temperature lithium-ion batteries (HT-LIBs). The IL based electrolytes show high thermal stabilities, up to 340 degrees C, ionic conductivities of > 5 x 10(-3) S cm(-1) at 80 degrees C, and broad electrochemical stability windows: 0-5 V vs. Li+/Li degrees. The performance of LiFePO4 based half-cells at 80 degrees C is promising, delivering ca. 160 mAh g(-1) at 1C, with a rate capability up to 4C and ca. 98% coulombic efficiency. The creation of hybrid IL/organic electrolytes by adding different organic cyclic carbonate solvents reduces viscosity of the electrolytes by 28% at 80 degrees C, thereby improving the ion transport, and further improves the electrochemical performance; higher stability, better rate capability, and >= 99% coulombic efficiency. Overall, the electrolytes proposed have a potential to be applied in HT-LIBs, a concept with large advantages at the vehicle system level. (C) 2016 Elsevier Ltd. All rights reserved.
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| 3. |
- Scheers, Johan, 1979, et al.
(författare)
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All fluorine-free lithium battery electrolytes Dedications: In memoriam of Prof. per Jacobsson.
- 2014
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753. ; 251, s. 451-458
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Tidskriftsartikel (refereegranskat)abstract
- Fluorine-free lithium battery electrolytes have been prepared from lithium salts with nitrile based anions, LiB(CN)4 or LiDCTA, dissolved in PEGDME or PC. After soaked into electrospun PAN membranes the resulting electrolytes were tested for physical and electrochemical properties and compared with reference PAN electrolytes containing LiPF6 or LiTFSI. The fluorine-free electrolytes were successfully cycled in Li/LiFePO4 cells at room temperature with up to 98% Coulombic efficiency. Small and qualitatively different effects were observed with the addition of Al 2O3 particles to the PAN membranes, which could be of importance for long-term performance. However, for fluorine-free electrolytes to be truly competitive, the relatively low anodic stability and elevated temperature performance must first of all be improved by a change of solvent - or addition of co-solvents. Further work in this direction is encouraged by the strong influence of the solvent (PC or PEGDME) on the properties of the LiDCTA electrolytes demonstrated in this work. © 2013 Elsevier B.V. All rights reserved.
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