| 摘要 |
It is the objective of the present invention to provide a membrane with high ion selectivity, high physicochemical stability and low cost is of vital importance. This objective is achieved according to the present invention by an ion exchange membrane with selective ion transport properties, in particular for use in a redox flow battery, comprising: a) a mechanically robust and chemically resistant base polymer film (matrix); b) ion exchange groups covalently bound to the polymer matrix, being anion exchange groups or cation exchange groups or a mixture thereof; c) blocking groups covalently bound to the polymer matrix preventing the passage of redox-active species across the membrane;and d) optionally additional functional constituents, such as crosslinkers or antioxidants; Therefore, this membrane has a highion selectivity, high physicochemical stability and low cost due to the selection of a base polymer film and the ion exchange groups as well as the blocking groups preventing the passage of redox-active species across the membrane. Preferably, the membrane is produced via radiation induced grafting, comprising the steps of: a) exposing the base polymer to ionizing radiation to introduce active sites; b) exposing the irradiated base polymer to a mixture of monomers comprising i) a monomer containing an ion exchange group or a precursor monomer yielding an ion exchange group in a subsequent step, ii) a monomer containing a functional group to block the passage of redox-active species through the membrane or a precursor monomer yielding the functional blocking group in a subsequent reaction step; iii) optional additional monomers, such as a crosslinker and antioxidant;and c) in case of the use of precursor monomers for ion exchange sites and blocking groups, post-treatment of the grafted film to introduce ion exchange sites and/or blocking groups is performed. |
