Table 1. Selected Properties of Tested Binders in This Study.
| binder | ALG | SO3-ALG | ester-ALG | ester-SO3-ALG | PVdF45 | |
|---|---|---|---|---|---|---|
| sulfur content (wt %)a | 0.3 | 10.1 | 0.1 | 9.2 | ||
| sulfation efficiency (%)b | 0 | 37 | 0 | 29 | ||
| ion-exchange capacity (meq g–1)c | 0 | 3.2 | 0 | 2.9 | ||
| molecular weight (×104 Da)d | Mn | 3 | 2.5 | 12 | 10 | |
| Mw | 6.2 | 4.8 | 44 | 31 | ||
| polydispersity indexd | 2.1 | 1.9 | 3.7 | 3 | ||
| solvent uptakee/% | 17 | 28 | 29 | 39 | 20 | |
| solubilityf/% | 99 | 96 | 98 | 98 | 97 |
Determined by elemental analysis.
Calculation detail can be found in the Supporting Information.
The reaction product was dissolved in water, and the solution was dropwisely added to 1 M aqueous HCl to precipitate SO3-ALG and ester-SO3-ALG. The precipitate was collected by filtration, washed with ethanol, dried, and immersed in saturated NaCl solution for 2 h. The aqueous solution was separated, and the HCl produced was quantified by titration with NaOH/phenolphthalein to determine the cation-exchange capacity.
Determined by gel permeation chromatography.
Compare the masses of the film between before (w0) and after (w1) immersion. The mass increment corresponds to the solvent uptake: solvent uptake (%) = [(w1 – w0)/w0] × 100.45
The film was dried again at 80 °C in a vacuum to remove EC/DMC. The resulting mass (w2) was used to calculate the solubility of the binder: solubility (%) = [(w0 – w2)/w0] × 100.45