Regensburg 2016 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 23: Charged Soft Matter

CPP 23.2: Hauptvortrag

Dienstag, 8. März 2016, 14:15–14:45, H40

Challenges and opportunities of nanostructured block copolymer membranes for lithium-ion batteries — •Ezzeldin Metwalli, Majid Rasool, Simon Brunner, and Peter Müller-Buschbaum — TU München, Physik-Department, LS Funktionelle Materialien, 85748 Garching, Germany

The ionic conductivity in relation to the morphology of lithium-doped high-molecular-weight polystyrene-block-polyethylene oxide PS-b-PEO diblock copolymer films was investigated as solid state membranes for lithium ion microbatteries.[1] The tendency of the polyethylene (PEO) block to crystallize is highly suppressed with increasing both the salt doping level and the temperature. The PEO crystallites completely vanish at a salt doing ratio of Li/EO > 0.08, where the PEO segments are hindered from entering the crystalline unit of PEO chain. The increase of the lamella spacing D of the Li-ion/BC hybrid films with increasing Li salt doping level is attributed to the PEO chain conformation rather than the salt volume contribution or the previously reported increase of the effective interaction parameter. Upon salt upload, the PEO chains change from a compact/highly folded conformation to an amorphous/expanded-like conformation. The ionic conductivity is enhanced by the PEO amorphorization. We will further emphasize on the challenges related to the low conductivity of the Li-ion/BC membranes at room temperature which limit their practical implementation. Possible solutions are also suggested. [1] E. Metwalli et al., ChemPhysChem 16, 2882 (2015)