title: The zwitterion effect in high-conductivity polyelectrolyte materials.
abstract: The future of lithium metal batteries as a widespread, safe and reliable form of high-energy-density rechargeable battery depends on a significant advancement in the electrolyte material used in these devices. Molecular solvent-based electrolytes have been superceded by polymer electrolytes in some prototype devices, primarily in a drive to overcome leakage and flammability problems, but these often exhibit low ionic conductivity and prohibitively poor lithium-ion transport. To overcome this, it is necessary to encourage dissociation of the lithium ion from the anionic polymer backbone, ideally without the introduction of competing, mobile ionic species. Here we demonstrate the effect of zwitterionic compounds, where the cationic and anionic charges are immobilized on the same molecule, as extremely effective lithium ion 'dissociation enhancers'. The zwitterion produces electrolyte materials with conductivities up to seven times larger than the pure polyelectrolyte gels, a phenomenon that appears to be common to a number of different copolymer and solvent systems.
authors.affiliation: School of Chemistry, Monash University, Wellington Road, Clayton, Victoria 3800, Australia.
authors.forename: Churat
authors.initials: C
authors.lastname: Tiyapiboonchaiya
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Pringle
authors.forename: Jiazeng
authors.initials: J
authors.lastname: Sun
authors.forename: Nolene
authors.initials: N
authors.lastname: Byrne
authors.forename: Patrick C
authors.initials: PC
authors.lastname: Howlett
authors.forename: Douglas R
authors.initials: DR
authors.lastname: MacFarlane
authors.forename: Maria
authors.initials: M
authors.lastname: Forsyth
mesh_terms: D045424:Complex Mixtures / Q000737:chemistry*; D004553:Electric Conductivity; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods*; D004573:Electrolytes / Q000737:chemistry*; D007477:Ions; D008094:Lithium / Q000737:chemistry*; D008422:Materials Testing; D011108:Polymers / Q000737:chemistry; D012997:Solvents / Q000737:chemistry*; D055672:Static Electricity
chemical_list: D045424:Complex Mixtures; D004573:Electrolytes; D007477:Ions; D011108:Polymers; D012997:Solvents; D008094:Lithium