Bio‐Derived and Cost‐Effective Membranes with High Selectivity for Redox Flow Batteries Based on Host–Guest Chemistry. Issue 43 (23rd February 2022)

• Record Type: Journal Article
• Authors: Gao, Li; Ding, Yu; He, Gaohong; Yu, Guihua
• Is Part Of: Small. Volume 18:Issue 43(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-02-23
• Subjects: chitosan -- flow batteries -- host–guest chemistry -- starch -- zinc–iodine; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.202107055
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: Redox flow batteries (RFBs) stand out as a promising energy storage system to solve the grid interconnection problems of renewable energy. Membranes play a critical role in regulating the performance of RFBs, and the selectivity is commonly controlled via either size exclusion or Donnan exclusion. Membranes typically account for 40% of the stack cost of RFBs, and it is essential to develop cost‐effective membranes with high selectivity to achieve widespread application. Here, a type of membrane composed of highly abundant materials derived in nature, based on a scalable fabrication process, is reported. Moreover, high selectivity is achieved attributed to the host–guest interactions between membranes and redox species, which effectively alleviate the crossover of redox‐active molecules. By incorporating starch into a chitosan matrix for zinc‐iodine RFBs, the highly selective recognition of starch and chitosan (host) toward triiodide (guest) builds a "wall" to block the triiodide‐based active materials, meanwhile, the conducting properties of such a membrane are not compromised. The proof‐of‐concept battery delivers a Coulombic efficiency of 98.6% and energy efficiency of 77.4% at a current density of 80 mA cm –2, showing the promise of such a novel and cost‐effective membrane design beyond traditional selectivity chemistry. Abstract : A ndesign concept for membranes in redox flow batteries is proposed to alleviate the crossover through "host–guest" interactions between membranes and redox species. As a proof‐of‐concept, a type of composite membrane composed of highly abundant materials derived in nature is prepared and applied in zinc‐iodine flow batteries. The designed redox flow battery delivers high Coulombic efficiency and energy efficiency.