Anionic and cationic block copolymers as durable electrolyte membranes

Durable block copolymers combining ionic and non-ionic blocks hold a great promise as membrane materials in next-generation fuel cells and batteries. With a proper macromolecular design, these copolymers self-assemble to form ordered nanostructures in which ion and water transport is facilitated over a wide range of conditions. For example, membranes based on sulfonated block copolymers typically shows a significantly higher proton conductivity under reduced humidity than corresponding statistical sulfonated copolymers when compared at the same ion content.1 This provides a considerable advantage for the former materials in fuel cell applications. Moreover, ionic block copolymer electrolytes enable highly efficient solid polymer lithium-metal batteries which can operate up to 80o C.2 Our research group has since many years developed methods for the preparation of phosphonated and sulfonated aromatic block copolymers and studied the influence of the structural parameters on the morphology, water uptake and ion conductivity of the membranes.3-6 In the present contribution the synthetic strategies and properties of both anionic and cationic block copolymer membranes targeted toward applications in fuel cells and other electrochemical devices will be discussed. 1. Elabd, Y. A., Hickner, M. A. (2013), Macromolecules, 44, 1-11. 2. Bouchet, R., Maria, S., Meziane, R., et al. (2013), Nature Mater., 12, 452-457. 3. Shao, Z. C., Sannigrahi, A., Jannasch, P. (2013), J. Polym. Sci., Polym. Chem., 51, 4657-4666. 4. Sannigrahi, A., Takamuku, S., Jannasch, P. (2013), Polym. Chem., 4, 4207-4218. 5. Takamuku, S., Jannasch, P. (2012), Adv. Energy Mater., 2, 129-140. 6. Persson, J. C, Jannasch, P. (2009), Chem. Mater., 18, 3096-3102