Oxygenated polymers for solid-state batteries Charlotte K. Williams Department of Chemistry, University of Oxford, UK
Polymers showing the right combination of electrochemical, mechanical and chemical properties could help deliver practical all-solid-state batteries for high-performance next-generation energy storage devices. These batteries require better polymers as both electrolytes and binders to better manage the active particle volume changes upon charge/discharge cycles and improve interfacial contact within composite cathodes. Further, currently used binders, e.g. polyvinylidene fluoride (PVDF), may be challenged by the proposed European Chemicals Agency bans on per- and poly fluoroalkyl substances (PFAS) – our research focusses on the discovery of alternative oxygenated polymers.1 This lecture will present the production, properties and performances of various new polycarbonates, -ethers and -esters within copolymers, for use in solid state batteries.2 Controlled polymerizations are used to produce well defined copolymers with the ability to moderate compositions, structures and resulting properties. These polymerizations exploit recent discoveries of highly active and selective polymerization catalysts.3, 4 These syntheses apply monomers including carbon dioxide, epoxides, cyclic esters and carbonates to deliver ABA block polymer structures (where A = polymer featuring a Tg> room temperature and B = block polymer featuring Tg < room temperature).2 Polymer thermal and mechanical properties will be outlined, together with data on phase separated nanostructures. Polymer properties relevant to batteries will include lithium-ion conductivity, transference numbers, electrochemical/chemical stability be presented, including lithium-ion conductivity and transference number, electrochemical/chemical stabilities and interfacial adhesion. The highest performing block polymers are used in composite cathodes using NMC (LiNi0.8Mn0.1Co0.1O2) as the active cathode with lithium Agyrodite (Li6PS5Cl) as the solid electrolyte– the resulting solid-state batteries demonstrate high capacities and excellent capacity retention. Performances are benchmarked against currently used binders and electrolytes.2 The potential to ‘recycle’ these polymers is outlined as a future option which may help improve sustainability and battery recycling.5 References 1. X. Lim, Nature, 2023, 620, 24-27. 2. G. L. Gregory, H. Gao, B. Liu, X. Gao, G. J. Rees, M. Pasta, P. G. Bruce and C. K. Williams, J. Am. Chem. Soc., 2022, 144, 17477-17486. 3. A. C. Deacy, G. L. Gregory, G. S. Sulley, T. T. D. Chen and C. K. Williams, J. Am. Chem. Soc., 2021, 143, 10021-10040. 4. W. T. Diment, W. Lindeboom, F. Fiorentini, A. C. Deacy and C. K. Williams, Acc. Chem. Res., 2022, 55, 1997-2010. 5. T. M. McGuire, A. C. Deacy, A. Buchard and C. K. Williams, J. Am. Chem. Soc., 2022, 144, 18444-18449.
P15
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