(266c) Channel Engineering in Solid Polymer Electrolytes for Electrochemical Energy Storage and Conversion Devices

Ion conducting solid-polymer electrolytes (SPE) provide an enabling technology for safer and more compact low temperature fuel cells, hydrogen producing water electrolyzers, lithium ion batteries and flow batteries. The critical parameters of solid polymer electrolytes include ionic conductivity, ion selectivity, chemical resistance and dimensional stability in the presence of excess solvent or plasticizers. An SPE also provides an opportunity for achieving single ion conduction. Single ion conduction would lead to near unity transference number for the electroactive ion which would mitigate the major cause of concentration polarization and the resulting voltage drop at high current density. Conductivity is the product of the number of charge carriers times the mobility of each charge carrier. Although a relatively high density of ions within the SPE can be achieved, the optimum number is often limited by other factors including mechanical strength, solvent swelling and negative impact on ion mobility at high ion density. Ion mobility depends on microarchitecture within the SPE. Channel engineering can produce high mobility (and thus high conductivity) by forming efficient channels in terms of channel size and tortuosity. In this presentation, the SPE challenges in two systems (i) aqueous, alkaline fuel cell and electrolyzers and (ii) non-aqueous lithium ion batteries will be presented.