Electrolyte‐resistant epoxy for bonding batteries based on sandwich structures

Abstract

Adhesives that are stable in Li-ion battery electrolytes are required to realize the potential of new battery designs that integrate structural elements with energy storage. Here, several polymers, commercial adhesives, and sealants were investigated to bond and seal a Li-ion battery sandwich panel. Gravimetric electrolyte uptake measurements were compared with Hansen solubility parameters to predict long-term durability of the materials exposed to battery electrolyte. The durability of adhesively bonded joints with an epoxy adhesive, which was selected as the lowest electrolyte uptake material, was examined using single lap shear strength tests and three-point bending tests in a fabricated sandwich panel. The strength of the epoxy decreased after exposure to battery electrolyte due to solvent uptake in the bond. The addition of lithium hexafluorophosphate to the ethylene carbonate/dimethyl carbonate mixture severely decreased the strength with respect to the pure solvents. In device testing, the sandwich panel did not show any visible damage or leakage when loaded to above 1000 N during three-point bending tests. Using sol extraction measurements and differential scanning calorimetry analyses, the optimized curing temperature for the epoxy adhesive ranged from 80 to 100 8C. At these temperatures, the cured adhesive had a highly crosslinked structure with low sol extraction.

Nitroxide Radical Polymer–Solvent Interactions and Solubility Parameter Determination

“…In addition to predicting the solubility parameters of other macromolecular radicals, the solubility parameters for PTMA and PTMA + were also used to evaluate common conductive additives, polymer binders, and processing solvents for the fabrication of homogeneous PTMA-based composite electrodes, Figure b. Here, we considered the Hansen solubility parameters for single-walled carbon nanotubes (SWCNTs), ,, multiwalled carbon nanotubes (MWCNTs), , graphene, Ti 3 C 2 T x MXene nanosheets, , fullerene (C60), , Super P carbon black, graphene oxide (GO), and reduced graphene oxide (rGO) as conductive additives and PVDF, PTFE, and PMMA as binder polymers. , Most of these have been used as additives in PTMA cathodes previously. − ,,,,,,− For the best interactions among components, the Hansen parameters should be similar (or have overlapping solubility spheres) to result in an increased cohesion among all of the components and to promote the formation of a percolating network of conductive additives. , …”

“…To improve upon these shortcomings, the Hansen solubility parameters δ h , δ p , and δ d , which account for the hydrogen-bonding, polarity, and dispersion forces, respectively, were developed. These parameters can also be combined to calculate a total Hansen solubility parameter (δ t ) …”

High-Performance Epoxy Vitrimers with the Joint Action of Dual Dynamic Covalent Bonds

“…Epoxy resin, as a widely used sealing material for electronic components, exhibits excellent characteristics in sealing, heat resistance, electrical insulation, and adhesion, making it more suitable for use in the packaging of rechargeable batteries. − In addition, the structural elements and energy storage of batteries also need to be stably bonded together, and epoxy resin is a promising candidate. E51-DAAx-DTDAy, as a new epoxy vitrimer, first had better insulation performance.…”

A critical review of structural supercapacitors and outlook on future research challenges

“…Efforts have been made to use prepreg, such has glass-fibre epoxy. However, the ionic liquid in the multifunctional device can be leached out by the uncured (or even B-staged) epoxy, dramatically reducing the device performance [50,61], although such effects have not been observed by some researchers [142][143][144][145].…”