Nanostructured Single-ion Polymer Blend Electrolytes Composed of Polyanionic Particles and Low Molecular Weight PEO.

The development of single-ion solid polymer electrolytes with high ion conductivity holds the key to the realization of safe, long-lasting, high-energy batteries. Here we introduce the use of core-shell nanostructured polyanionic particles, composed of polyanion asymmetric miktoarm stars with a large number of glassy polystyrene-based polyanion arms that complement longer poly(ethylene oxide), PEO, arms, as additives to low molecular weight, liquid PEO. Due to the proposed macromolecular design approach, the polyanion particles are well dispersed for wt % ≤ 55 that enables the formation of a nanostructured single-ion electrolyte with highly interconnected channels composed of liquid PEO that promotes fast ion transport. Noticeably, while the ion conductivity remains fairly unaffected and close to 10-5 S/cm at room temperature with nanoparticle loading, the shear modulus monotonically increases by several order of magnitudes indicating a very strong decoupling between the antagonistic properties of mechanical modulus and ion conductivity.

Functionalization of Single-Walled Carbon Nanotubes with End-Capped Polystyrene via a Single-Step Diels-Alder Cycloaddition.

A facile, single-step, [4+2] Diels-Alder cycloaddition reaction for the surface functionalization of single-walled carbon nanotubes (SWNTs) with end-capped polystyrene chains is presented. The thermal cycloaddition reaction took place at high temperature (~230 °C) without any catalyst between the sp2 network of carbon nanotubes, which acted as dienophile, and the diphenylethylene cyclobutene (DPE-CB) terminal group of the polystyrene chain. Anionic polymerization was employed for the synthesis of the polystyrene macromolecule, and successful and quantitative end-capping reaction with the DPE-CB molecule was confirmed by matrix-assisted laser desorption/ionization time of flight mass spectroscopy. Thermogravimetric analysis revealed the wt % of the grafted macromolecule on the CNT surface as well as the grafting density of the polymer chains on the SWNTs (0.027 chains nm-2). Direct evidence for the surface functionalization and the presence of thin polystyrene film was obtained by transmission electron microscopy (TEM) and by atomic force microscopy (AFM).

Designing All-Polymer Nanostructured Solid Electrolytes: Advances and Prospects.

Multi-phase nanostructured polymer electrolytes, where the one phase conducts ions while the other imparts the desired mechanical properties, are currently the most promising candidates for solid-state electrolytes in high-density lithium metal batteries. In contrast to homogeneous polymer electrolytes, where ion transport is coupled with polymer segmental dynamics and any attempt to improve conductivity via faster polymer motions results in a decrease in stiffness, nanostructured materials efficiently decouple these two antagonistic parameters. Nevertheless, for reasons discussed herein the synthesis of a polymer electrolyte that simultaneously has a shear modulus of G' ≈ GPa and an ion conductivity of σ > 10-4 S/cm (in the case dual ion conductor) or of σ > 10-5 S/cm (in the case of single-ion conductor) remains a challenge. This review focuses on recent designing strategies for the synthesis of all-polymer nanostructured electrolytes, and protocols for introducing a single-ion character in such materials.