One major factor limiting the power of a galvanic cell is the Ohmic drop within the electrolyte. To enhance the performance, the distance between anode and cathode has to be reduced resulting in a thin film assembling. To prevent the two electrodes in such advanced devices from touching each other causing short-circuits, a separator is needed. This separator should be mechanically robust while not limiting the performance of the electrolyte too much. Up to now all known separators for battery applications are manufactured in a separate process and have to be assembled with the electrode material in an additional step prior to be post-filling with the electrolyte. Emulsion templating now offers a one-pot synthesis for UV-curable inks that can be directly printed onto the electrode material, resulting in highly porous in-situ electrolyte filled polyHIPE separators. Dependent on the way of fabrication, McMullin Numbers close to one can be achieved. Using a combination of Lauryl methacrylate and 1,12-Dodecanediol dimethacrylate as external phase, we have been able to apply 20% KOH (NiMH batteries, pH 14), 37% H<sub>2</sub>SO<sub>4</sub> (lead-acid-batteries, pH 1) and Lithium salt containing organic carbonate mixtures and room temperature ionic liquids (Lithium ion batteries, Lithium ion capacitors) as internal phase up to contents of 90%. All systems have been characterized in terms of microstructure, rheology, electrical conductivity and mechanical and thermal stability. By simple doctor blade casting, porous films with thicknesses down to at least 50 µm could be achieved, while microstructure rises the possibility to further reduce this value down to about 10 µm.

In situ electrolyte filled polyHIPEs as printable separators for rechargeable batteries

252nd National Meeting (2016)

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