Abstract The transient current overshot and the evolution of the ionic concentrations and the electric potential to the limiting current regime by linear sweep voltammetry have been numerically investigated in ion-exchange membrane systems. The system under study is constituted by a cation-exchange membrane and two diffusion boundary layers on both sides of the membrane, which include the electric double layers at the interfaces, ionic transport of a binary electrolyte being described by the Nernst-Planck and Poisson equations. The time evolution of the electric current through the system in response to an electric potential increasing linearly with time, has been numerically simulated for different sweep rates of the perturbing signal by using the network simulation method. The effect of the sweep rate on the current-voltage curves has been analysed and discussed for systems with different values of the thickness of the diffusion boundary layers and the membrane resistance. The dependence of the peak current and the peak potential with the sweep rate has been compared to experimental results. The evolution with the applied potential of the counter-ion concentration at the boundary of the electroneutral region of the depleted DBL close to the membrane has been also obtained for different rates of the perturbing potential. The potential differences across the different regions of the membrane system and the structure of the space charge regions inside the DBLs have been analysed in the limiting regime under potentiostatic control and discussed in relation to the Teorell-Meyer-Sievers model.

中文翻译：

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在离子交换膜系统中通过线性扫描伏安法达到极限电流状态

摘要 通过线性扫描伏安法对离子交换膜系统中的瞬态电流过冲以及离子浓度和电位向极限电流状态的演变进行了数值研究。所研究的系统由阳离子交换膜和膜两侧的两个扩散边界层构成，其中包括界面处的双电层，二元电解质的离子传输由 Nernst-Planck 和 Poisson 方程描述. 响应于随时间线性增加的电势，通过系统的电流的时间演变已经通过使用网络模拟方法针对扰动信号的不同扫描速率进行了数值模拟。对于具有不同扩散边界层厚度和膜电阻值的系统，分析和讨论了扫描速率对电流-电压曲线的影响。已将峰值电流和峰值电位与扫描速率的相关性与实验结果进行了比较。对于不同速率的扰动电位，还获得了在靠近膜的耗尽 DBL 的电中性区域的边界处反离子浓度的施加电位的演变。膜系统不同区域的电位差和 DBL 内部空间电荷区域的结构已在恒电位控制下的限制范围内进行了分析，并结合 Teorell-Meyer-Sievers 模型进行了讨论。