Atomistic Simulations of Microporous Polymer Membranes for Energy Storage and Conversion Charlotte Breakwell 1 , C. Ye 2 , A. Wang 3 , N.B. McKeown 2 , K.E. Jelfs 1 and Q. Song 3 1 Imperial College London, UK, 2 University of Edinburgh, UK, 3 Department of Chemical Engineering, Imperial College London, UK.
With the rapid development of renewable energy technologies, such as solar and wind power, energy conversion and storage technologies are in urgent need for the grid-scale integration of low carbon technologies. Ion exchange membranes are critical performance-governing components in a variety of electrochemical devices for electrical energy conversion and storage, such as redox flow batteries (RFBs), fuel cells, and water electrolysers. Many commercially available membranes, such as Nafion, suffer from high costs as well as a ubiquitous selectivity/permeability trade-off. Microporous materials provide a new approach towards designing ion-conductive membranes with confined and selective ion transport channels. Among them, polymers of intrinsic microporosity (PIMs) have emerged as a promising platform for designing ion-transport membranes that enable fast diffusion and ion selectivity owing to their high chain rigidity and low degree of phase separation. For example, recent work has shown that introduction of hydrophilic functionality by the chemical modification of PIMs generated selective membranes with fast salt ion conductivity and selectivity towards organic redox molecules. 1 The rational design of new hydrophilic PIMs will require a molecular-level understanding of the relationships between polymer structure and performance governing properties. To this end, computational simulations will be invaluable in uncovering these important structure-property relationships in a low-cost and time efficient manner. We generated molecular models of a series of new sulfonated PIM polymers with spirobifluorene backbone with varied degrees of sulfonation and hydration. Through the models, we quantified the size of water clusters and connectivity of the water channels, which are critical for fast ion transport. Ongoing efforts are being devoted to model the dynamic ion transport properties by applying non-equilibrium concentration gradients and electrical fields. References 1. Hydrophilic microporous membranes for selective ion separation and flow-battery energy storage, R. Tan, A. Wang, R. Malpass-Evans et al . Nature Materials (2020), 19, 195-202.Development of efficient aqueous organic redox flow batteries using ion-sieving sulfonated polymer membranes, C. Ye, A. Wang, C. Breakwell et al ., Nature Commun. ( 2022), 13 , Long- Life Aqueous Organic Redox Flow Batteries enabled by Amidoxime-Functionalized Ion-Selective Polymer Membranes, C. Ye, R. Tan, A. Wang, J. Chen, B. Comesaña Gándara, C. Breakwell et al ., Chem. Int. Ed. (2022), 134 , e202207580. 2. Ion-selective Microporous Polymer Membranes with Hydrogen-bond and Salt-bridge Networks for Aqueous Organic Redox Flow Batteries, A. Wang, R. Tan, D. Liu, J. Lu, X. Wei, A. Alvarez-Fernandez, C. Ye, C. Breakwell et al ., Mater. (2023), https://doi.org/10.1002/adma.202210098 (Accepted).
E19
© The Author(s), 2021
Made with FlippingBook Learn more on our blog