Production of a thin-film Li-ion battery involves multiple processing steps which are both complex and costly. One such part of the battery is the separator, a permeable membrane which lies between the battery’s cathode and anode.
A measure of the ratio of the resistance of the electrolyte-filled separator to the resistance of the electrolyte alone is called the MacMullin number. The aim is to lower this number in batteries. This technology allows for the preparation of in situ Li+-electrolyte filled polymer separator membranes with MacMullin numbers that are at least by a factor of 2 lower than for current commercially used separators.
This technology provides a one pot synthesis of an electrolyte filled macroporous polymer separator using a technique called emulsion templating which allows for the synthesis of in-situ electrolyte filled separators. Additionally it opens the door for simplification of the manufacturing of (thin film) Li-ion batteries. The templates can be used as inks and be directly printed or cast onto the battery’s electrodes.
Solidification of the macroporous scaffold for the electrolyte is achieved by UV polymerisation.