Stability of uniform electrode states in the presence of ohmic drop compensation
Stability of uniform electrode states in the presence of ohmic drop compensation
复制标题
DOI：
10.1016/j.electacta.2003.04.006
复制
发表时间：
2003-12
影响因子：
6.6
通讯作者：
K. Krischer;H. Varela;A. Bîrzu;F. Plenge;A. Bonnefont
中科院分区：
文献类型：
--
作者：
K. Krischer;H. Varela;A. Bîrzu;F. Plenge;A. Bonnefont
已知的是，通过Haber-Luggin毛细管（即，探测接近工作电极（WE）的溶液电势的参比电极（RE））对欧姆溶液电阻的补偿引起可能使均匀电极状态不稳定的全局反馈。在本文中，我们证明了当将参比电极（RE）放置在细胞的轴上并靠近环形工作电极（WE）时，细胞电阻得到补偿，并以完全相同的方式在局部电极电位的演化方程中表现出来，外部串联电阻的大小相同，但负阻抗会这样做。这意味着不仅可以容易地测量全局反馈的强度，从而预测其对系统行为的影响，而且任何外部电子单元补偿都对系统施加相同的不稳定全局耦合，而与电极的相对布置和几何形状无关。这种说法的证据是在三个步骤：第一，所提到的电极几何形状的电池电阻和补偿电阻的全球耦合的一般配方推导。然后，在现实的三维模拟以及在实验中的电池电阻补偿（a）由一个封闭的RE和（B）由外部负阻抗的电化学系统的时空动态进行比较。
It is known that the compensation of the ohmic solution resistance by means of a Haber–Luggin capillary (i.e. a reference electrode (RE) that probes the solution potential close to the working electrode (WE)) causes a global feedback that might destabilize the uniform electrode state. In this paper we demonstrate that the cell resistance which is compensated when placing the reference electrode (RE) on the axis of the cell and close to a ring-shaped working electrode (WE) manifests itself in the evolution equation of the local electrode potential in exactly the same way an external series resistor of the same magnitude but negative impedance would do. This implies not only that the strength of the global feedback can easily be measured and thus its impact on the system’s behavior predicted but also that any external electronic cell compensation exerts the same destabilizing global coupling on the system, independent of relative arrangement and geometry of the electrodes. Evidence of this statement is given in three steps: First, a general formulation of the global coupling for the mentioned electrode geometry in terms of the cell resistance and the compensated resistance is derived. Then the spatio-temporal dynamics of electrochemical systems in which the cell resistance is compensated (a) by a close RE and (b) by an external negative impedance are compared in realistic three-dimensional simulations as well as in experiments.