Ion-Conducting Dynamic Solid Polymer Electrolyte Adhesives

Abstract

Cross-linked polymer electrolytes containing structurally dynamic disulfide bonds have been synthesized to investigate their combined ion transport and adhesive properties. Dynamic network polymers of varying cross-link densities are synthesized via thiol oxidation of a bisthiol monomer, 2,2′-(ethylenedioxy)diethanethiol, and tetrathiol cross-linker, pentaerythritol tetrakis(3-mercaptopropionate). At optimal loading of lithium bis(trifluoromethane-sulfonyl-imide) (LiTFSI) salt, the ionic conductivities (σ) at 90 °C are about 1 × 10 −4 and 1 × 10 −5 S/cm at the lowest and highest cross-linking, respectively. Notably, in comparison to the equivalent nondynamic network, the dynamic network shows a positive deviation in σ above 90 °C, which suggests the enhancement of ion transport occurs from the difference in structural relaxation on account of the dissociation of disulfide bonds. Lap shear adhesion and conductivity tests on ITO-coated glass substrates reveal the dynamic network exhibits a higher adhesive shear strength of 0.2 MPa (vs 0.03 MPa for the nondynamic network) and higher σ after the application of external stimulus (UV light or heat). The adhesive strength and σ are stable over multiple debonding/rebonding cycles and, thus, demonstrating the utility of these structurally dynamic networks as solid polymer electrolyte adhesives.

Light-Mediated Synthesis and Reprocessing of Dynamic Bottlebrush Elastomers under Ambient Conditions

“…The high concentration of disulfides along the bottlebrush backbone in lipoic-acid-based materials enables a unique mechanism of dynamic exchange. As shown in Figure a, cross-linked bottlebrush molecules can swap S–S backbone bonds under an applied stimulus, in principle, either UV light or heat. ,,,,,,, Both cut (Figure a, Figures S27–S29) and chopped (Figure S30) material can be reformed by self-healing. As evidenced by stress relaxation experiments, 320–500 nm irradiation (Figure b) and heat (Figure S32) are highly effective at promoting dynamic covalent bond rearrangement with a rate that depends on the intensity of light or temperature.…”

“…An attractive option is light as a platform to drive chemical transformations under mild conditions, which would provide tunable spatial and temporal control over stress relaxation at room temperature through masking and modulating the intensity/wavelength of irradiation. While there have been significant achievements in light-mediated dynamic bonds − and corresponding structure–property studies based on linear networks, ,− to the best of our knowledge, none have been applied to complex bottlebrush architectures.…”

Effects of crosslinking density and Lewis acidic sites on conductivity and viscoelasticity of dynamic network electrolytes

“…Such dynamic network electrolytes (DNEs) have been shown to be selfhealing, dissolvable back to monomer, and stimuliresponsive. 17,24,25 Bond exchange can also provide an additional dynamic process in the materials which may impact ion transport if the timescales are comparable. A complex interplay between salt addition, dynamic bond kinetics, temperatures, and crosslink density allows for a large degree of tunability in conductivity and rheological properties of DNEs.…”

“…One route to build upon permanent network electrolytes is the incorporation of dynamic bonds into the backbone or at crosslink points. Such dynamic network electrolytes (DNEs) have been shown to be self‐healing, dissolvable back to monomer, and stimuli‐responsive 17,24,25 . Bond exchange can also provide an additional dynamic process in the materials which may impact ion transport if the timescales are comparable.…”

High ionic conduction, toughness and self-healing poly(ionic liquid)-based electrolytes enabled by synergy between flexible units and counteranions

“…Based on the above motivation, quite a few self-healable SPEs containing the covalent or non-covalent bonds such as disulde bonds, 5,6 hydrogen bonds, [7][8][9] and ionic bonds, [10][11][12] have been identied in the past decades. Among several different classes, polymerized ionic liquids or so-called poly(ionic liquid) s (PILs) formed from ionic liquid (IL) monomers are a promising candidate for intrinsic self-healing SPEs with the reversible ionic interactions between the charged polymer backbones and counter-ions.…”