Electrolyte Membrane with Selective Ion Transport Properties and a Redox Flow Battery Comprising an Electrolyte Membrane

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This patent describes an improved ion exchange membrane with selective ion transport properties, particularly designed for redox flow batteries. The membrane is built from a robust and chemically resistant polymer base, to which ion exchange groups and blocking groups are covalently attached. These blocking groups prevent redox-active species from crossing the membrane while allowing the required ions to pass. The membrane can be produced at low cost using a scalable radiation-induced grafting process, resulting in high ion selectivity, excellent physical and chemical stability, and improved performance compared to conventional membranes like Nafion.

Use CasesContent extracted from patent full text and abstract with AI.

• Membranes for redox flow batteries used in grid-scale or residential energy storage.
• Improved separators in aqueous or non-aqueous battery systems requiring high ion selectivity, such as vanadium redox flow batteries.
• Replacement of high-cost membranes (like Nafion) in industrial and research energy storage devices.
• Energy storage systems for renewable energy integration in power grids.
• Backup power supplies and uninterruptible power systems (UPS) based on redox flow technology.

BenefitsContent extracted from patent full text and abstract with AI.

• High ion selectivity ensures efficient charge transfer and reduces cross-contamination between battery compartments, leading to better battery efficiency and lifespan.
• Improved physicochemical stability provides resistance to chemical degradation and mechanical stress, enhancing durability.
• Lower cost and scalable production method (radiation-induced grafting), making the technology more commercially viable compared to expensive membranes like Nafion.
• Reduced crossover of redox-active species minimizes self-discharge rates and increases overall energy efficiency of batteries.
• Adjustable membrane properties (ion selectivity and blocking capability) by tuning the composition and processing conditions, enabling optimized performance for different battery chemistries.

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Patent Abstract

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 high ion 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.