## 2 Experimental Section
### Solvent and Ion Sorption  
Pretreatment: All anion-exchange membranes (AEMs) in this part of the experiment were cut into circular discs with a diameter of 3 cm. The AEMs were transformed into chloride ion carriers in a 3 mol\(\cdot\)L\({}^{-1}\) NaCl solution. Subsequently, the AEMs were immersed in deionized (DI) water repeatedly (for 4 h at a time) until the conductivity of the solution was reduced to below 2 \(\mu\)S\(\cdot\)cm\({}^{-1}\) to elute mobile electrolytes. Afterward, excess moisture was wiped from their surfaces using absorbent paper, and the wet weight of the AEM (\(m_{\text{wet}}\)) for all membranes was quickly measured using an analytical balance. The AEMs were then placed in a vacuum dryer for 48 h, which is typically sufficient to stabilize their mass, and the weight of the dried AEM (\(m_{\text{dry}}\)) was measured. The water uptake (\(W\%\)) of the AEM can be calculated as follows:  
\[W\%=\frac{m_{\text{wet}}-m_{\text{dry}}}{m_{\text{dry}}-m_{\text{b}}} \tag{1}\]  
where \(m_{\text{b}}\) represents the weight of the polypropylene (PP) support fiber, which is generally regarded as not contributing to water absorption but is essential for the structural strength of the AEM. For accurate attribution and quantitative calculation of all contributions, the water absorption values reported in this experiment should exclude the internal supporting fibers [10]. Equilibrium: As the Figure 2, the dry, non-mobile salt anion-exchange membranes (AEMs) were placed in NaCl solutions of varying concentrations, with volumes and total ion content significantly exceeding that of the AEMs; typically, 50 mL is sufficient. This process requires a minimum of 24 h. Afterward, as previously described, the solution on the surface was wiped off to measure the weight of the swollen AEMs (\(m_{\text{sw}}\)). The method for calculating the absorption rate of the solution is similar to that in Equation (1). All experimental procedures and controls were the same for sodium bromide solutions when used as equilibrium solutions. The next discussion will involve the concepts of \"co-ions\" and \"counter-ions\", which are related to the fixed groups of the ion-exchange polymer. For example, in this experiment using ACLP AEMs, the fixed charge group [-N\({}^{+}\)(CH\({}_{3}\))\({}_{3}\)] is positive, making Na\({}^{+}\) the co-ions and Cl\({}^{-}\) the counter-ions. Similarly, if the ion-exchange polymer is a sulfonic acid-type cation-exchange membrane (CEM), then Na\({}^{+}\) are counter-ions and Cl\({}^{-}\) are co-ions. Similarly, assuming that the ion-exchange polymer is a sulfonic acid-type cation-exchange membrane (CEM), then Na\({}^{+}\) are counter-ions, and Cl\({}^{-}\) are co-ions. Figure 1: The process for preparing aminated cross-linked polystyrene (ACLP) involves bulk polymerization followed by amination [43]. Desorption: The AEMs were transferred to clean plastic bottles containing 20 mL of deionized (DI) water [10]. Glass instruments were not permitted in the following steps, as they are known to adsorb sodium ions, which can affect the measurement of co-ions, especially in low-concentration experimental groups [45]. Generally, a two-step desorption can nearly completely extract all mobile electrolytes in the AEMs, including all co-ions and some counter-ions, with the concentration of the second desorption solution being much lower than that of the first. The concentration of the mobile electrolytes was measured using ICP-MS and calculated as follows:  
\[m_{\text{Na}^{+}}^{\text{m}}=m_{\text{s}}^{\text{m}}=\frac{m_{1}^{\text{d}}c_ {1}^{\text{d}}+m_{2}^{\text{d}}c_{2}^{\text{d}}}{m_{\text{sw}}-m_{\text{dry}}} \tag{2}\]  
where \(m_{\text{s}}^{\text{m}}\) is the molality (mol\(\cdot\)kg\({}^{-1}\) H\({}_{2}\)O) of the mobile electrolytes; \(m_{1}^{\text{d}}\), \(m_{2}^{\text{d}}\) are the solution mass, respectively, first desorption solution and the second desorption solution; \(c_{1}^{\text{d}}\), \(c_{2}^{\text{d}}\) are their corresponding electrolyte concentrations.