title: A dendrite-suppressing composite ion conductor from aramid nanofibres.
abstract: Dendrite growth threatens the safety of batteries by piercing the ion-transporting separators between the cathode and anode. Finding a dendrite-suppressing material that combines high modulus and high ionic conductance has long been considered a major technological and materials science challenge. Here we demonstrate that these properties can be attained in a composite made from Kevlar-derived aramid nanofibres assembled in a layer-by-layer manner with poly(ethylene oxide). Importantly, the porosity of the membranes is smaller than the growth area of the dendrites so that aramid nanofibres eliminate 'weak links' where the dendrites pierce the membranes. The aramid nanofibre network suppresses poly(ethylene oxide) crystallization detrimental for ion transport, giving a composite that exhibits high modulus, ionic conductivity, flexibility, ion flux rates and thermal stability. Successful suppression of hard copper dendrites by the composite ion conductor at extreme discharge conditions is demonstrated, thereby providing a new approach for the materials engineering of solid ion conductors.
authors.affiliation: Macromolecular Science and Engineering, University of Michigan, 2300 Hayward, Ann Arbor, Michigan 48109, USA.
authors.forename: Siu-On
authors.initials: SO
authors.lastname: Tung
authors.affiliation: Electrified Powertrain Engineering, Ford Motor Company, 1201 Village Road, Dearborn, Michigan 48121, USA.
authors.forename: Szushen
authors.initials: S
authors.lastname: Ho
authors.affiliation: Key Laboratory of Microsystems and Micronanostructures Manufacturing, Harbin Institute of Technology, 2 Yikuang Street, Ann Arbor, Harbin 150080, P. R. China.
authors.forename: Ming
authors.initials: M
authors.lastname: Yang
authors.affiliation: Department of Material Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: Ruilin
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Kotov