2 research outputs found
Anisotropic Ion Transport in a Poly(ethylene oxide)–LiClO<sub>4</sub> Solid State Electrolyte Templated by Graphene Oxide
Solid polymer electrolytes (SPEs)
have attracted intensive attention
due to their potential applications in all-solid-state lithium batteries.
Tailoring crystallization is crucial to the design of high performance
polyÂ(ethylene oxide) (PEO)–based SPEs. In this paper, we demonstrate
that PEO crystal orientation in a PEO–lithium electrolyte results
in anisotropic ionic conductivity along and through the crystalline
lamellae. This conductivity anisotropy can be further enhanced by
incorporating two-dimensional graphene oxide (GO) nanosheets, which
retard PEO crystallization, template the crystal orientation, and
guide the ion transport, leading to highly anisotropic and conductive
nanocomposite polymer electrolytes
How Does Nanoscale Crystalline Structure Affect Ion Transport in Solid Polymer Electrolytes?
Polymer
electrolytes have attracted intensive attention due to
their potential applications in all-solid-state lithium batteries.
Ion conduction in this system is generally considered to be confined
in the amorphous polymer/ion phase, where segmental relaxation of
the polymer above glass transition temperature facilitates ion transport.
In this article, we show quantitatively that the effect of polymer
crystallization on ion transport is twofold: structural (tortuosity)
and dynamic (tethered chain confinement). We decouple these two effects
by designing and fabricating a model polymer single crystal electrolyte
system with controlled crystal structure, size, crystallinity, and
orientation. Ion conduction is confined within the chain fold region
and guided by the crystalline lamellae. We show that, at low content,
due to the tortuosity effect, the in-plane conductivity is 2000 times
greater than through-plane one. Contradictory to the general view,
the dynamic effect is negligible at moderate ion contents. Our results
suggest that semicrystalline polymer is a valid system for practical
polymer electrolytes design