Alexandra Lex-Balducci

Evaluation of the wetting time of porous electrodes in electrolytic solutions containing ionic liquid

The wetting time of porous electrodes with electrolytes based on organic solvents and ionic liquids, respectively, was investigated with two different techniques: with a tensiometer and by impedance spectroscopy. The results of this study showed that the wetting time of a porous electrode with ionic liquid-based electrolytes is up to 20 times longer than that with electrolytes comprising organic solvents. A significant reduction in the wetting time with ionic liquid-based electrolytes could be achieved by adding organic solvents. This effect can be explained by the interplay of reduced viscosity, increased surface tension and change in contact angle caused by the addition of the organic solvent, with the lower viscosity being the main driver of improved wetting kinetics.

Local Li Coordination and Ionic Transport in Methacrylate‐Based Gel Polymer Electrolytes

The local Li cation coordination motifs and the interactions between the hosting methacrylate-based polymer membrane and the liquid electrolyte [1 M LiPF6 in ethylene carbonate (EC)/dimethyl carbonate (DMC)] are studied by employing liquid and solid-state NMR spectroscopy. At low temperatures, two different coordination modes for Li cations are identified with the help of dipolar-based solid-state NMR techniques, one of which is the exclusive coordination by DMC molecules, while the other is a co-coordination by the polymer and DMC molecules. At room temperature, Li cations are found to be extremely mobile, coordinated by EC and DMC molecules as well as the copolymer, as found by liquid-state NMR spectroscopy.