| 1. |
- Brandell, Daniel, et al.
(författare)
-
Conduction Mechanisms in Crystalline LiPF6·PEO6 Doped with SiF62- and SF6
- 2005
-
Ingår i: Chem. Mater. - : American Chemical Society (ACS). ; 17:14, s. 3673-3680
-
Tidskriftsartikel (refereegranskat)abstract
- Molecular dynamics (MD) simulations have been made under imposed electric fields for crystalline LiPF6·PEO6, (LiPF6)1-x(Li2SiF6)x·PEO6, and (LiPF6)1-x(SF6)x·PEO6 for x = 0.01 under standard pressure and temperature conditions with the aim of identifying the conduction mechanisms in the systems. Contrary to the results of earlier experimental investigations where only cation mobility was observed, ionic transport is here found to occur in regions between the polymer hemi-helices, with a high transference number (0.9-1.0) for the PF6- anions.
|
|
| 2. |
- Karo, Jaanus, et al.
(författare)
-
A molecular dynamics study of the effect of side-chains on mobility in a polymer host
- 2005
-
Ingår i: Solid State Ionics. - : Elsevier BV. - 0167-2738. ; 176:39-40, s. 3041-3044
-
Tidskriftsartikel (refereegranskat)abstract
- The effect on polymer dynamics of adding methoxy-terminated poly(ethylene oxide) (PEO) side-chains with different lengths and separations to an amorphous long-chain PEO backbone has been studied by Molecular Dynamics (MD) simulation at 293 K and 330 K. The study is seen as having a direct general relevance to the optimal design of ion-conducting polymer hosts for both Li-ion battery and polymer fuel-cell applications. The MD box used contains a long-chain PEO backbone to which side-chains comprising 3, 6, 7, 8, 9 and 15 EO units are added. The chosen separations between the side-chains are 5, 10, 15, 20 and 50 EO units. All potentials used to describe these systems are taken from earlier work (J. Mater. Chem., 13 (2003) 214). The overall mobility of the polymer host system is found to have both minima and maxima at both temperatures for side-chain lengths in the range 6–9 EO units. This is almost totally independent of side-chain separation at 293 K, while the situation is more complex at 330 K.
|
|
| 3. |
- Liivat, Anti, et al.
(författare)
-
Development of a force field for Li2SiF6
- 2005
-
Ingår i: Journal of Computational Chemistry. - : Wiley. - 0192-8651 .- 1096-987X. ; 26:7, s. 716-724
-
Tidskriftsartikel (refereegranskat)abstract
- A force field has been developed for Li2SiF6 for subsequent use in Molecular Dynamics (MD) simulations involving Li+ and SiF ions in a polymer electrolyte host. Both ab initio calculations and available empirical data have been used. The force field has been verified in simulations of the crystal structure of Li2SiF6 in two different space groups: P321 and Pm1. The use of MD simulation to assess the correct space group for Li2SiF6 shows that it is probably P321.
|
|
| 4. |
- Tucker, Michael, et al.
(författare)
-
The Pore Structure of Direct Methanol Fuel Cell Electrodes
- 2005
-
Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651. ; 152:9, s. A1844-A1850
-
Tidskriftsartikel (refereegranskat)abstract
- The pore structure and morphology of direct methanol fuel cell electrodes are characterized using mercury intrusion porosimetry and scanning electron microscopy. It is found that the pore size distributions of printed primer and catalyst layers are largely dictated by the powders used to make the printing ink. The extent to which the pore structure is modified by changing several parameters in the membrane electrode assembly (MEA) manufacturing process is discussed. The pore structure of the printed layers is found to be invariant with respect to changes in powder loading or in choice of printing substrate, and is relatively undisturbed by MEA hot-pressing. Changing the source of the primer powder and adding a pore-forming agent to the catalyst ink are found to be successful methods of creating a more open pore structure in the printed layers.
|
|
