| 1. |
- Lewin, Erik, et al.
(författare)
-
Synthesis, structure and properties of Ni-alloyed TiCx-based thin films
- 2010
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 20:28, s. 5950-5960
-
Tidskriftsartikel (refereegranskat)abstract
- By using non-reactive sputter deposition at low temperatures metastable solid solution phases in the Ti–Ni–C system were synthesized. Produced thin films were either single phase carbides or nanocomposite of nanocrystalline carbide and amorphous C. In the Ni-containing samples a supersaturated solid solution phase (Ti1−xNix)Cy was identified, and was present either as single phase or in a nanocomposite with amorphous C. By modification of the chemical stability of the carbide phase, the addition of Ni was found to strongly promote the formation of amorphous carbon phase in the coatings. Samples have been microstructurally analyzed using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Mechanical properties have been evaluated through nanoindentation and pin-on-disc measurements; electrical properties were determined by measurement of the resistivity and the contact resistance. Alloyed nanocomposite coatings were also found to exhibit enhanced tribological and electrical properties, with a decreased resistivity and friction. This makes these thin films very interesting for application in sliding electrical contacts. The mechanisms responsible for the reductions remain to be determined.
|
|
| 2. |
- Urbonaite, Sigita, et al.
(författare)
-
Effect of ethanol-assisted electrode fabrication on the performance of silicon anodes
- 2010
-
Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 195:16, s. 5370-5373
-
Tidskriftsartikel (refereegranskat)abstract
- The performance of high-silicon-content anodes was tested as a function of silicon particle-size (44 mu m, 1.8 mu m and 70-100 nm), surface pre-treatment and solvent chosen for anode preparation. Two simple procedures, leading to significant improvements in electrode performance are reported. First, pretreatment of nano-Si in ethanol which unexpectedly yields functionalised surfaces improving cycling stability. Second, the use of a 30:70 solution of ethanol and water to dissolve the CMC-binder for the electrode preparation boosts specific battery capacity. Ethanol pre-treatment of nano-Si also resulted in improved adhesion of the electrode to the current collector as well as in de-agglomeration of nano-Si powder. All these treatments improved capacity stability during cycling. Changes in surface chemistry of nano-Si before and after ethanol treatment have been analysed by XPS. A stable capacity of about 1630 mAh g(-1) was obtained after 25 cycles for an electrode containing 80% silicon using ethanol during electrode coating preparation.
|
|
| 3. |
- Younesi, Reza, et al.
(författare)
-
The Effect of Pore Size on the Performance of the Li-O2 Battery
- 2010
-
Ingår i: ECS Transactions. - : The Electrochemical Society. - 1938-5862 .- 1938-6737. ; 25:35, s. 121-127
-
Tidskriftsartikel (refereegranskat)abstract
- Lithium-airbatteries are complex electrochemical systems. This study deals with thecomposite cathode, where oxygen is reduced and different lithium-oxygen speciesare formed as reaction products. The amount of stored reactionproduct and thus the battery capacity is known to dependon surface area and pore-volume in the cathode. Here therole of pore size is studied for three different carbonsand their corresponding composite cathode films. Gas adsorption studies showthat film-forming Kynar polymer is blocking micropores and mesopores below~300 Å. This influences battery performance of the high surfacearea carbon, containing micropores only, where the capacity is shownto be negligible. The two other carbons, with wider pore-sizedistributions, show a battery capacity in the order of 1300-1500mAh/g carbon. This shows that it is vital to consideralso the pore size in the cathode film for agood battery performance.
|
|
| 4. |
|
|
