Convective Current in a Four-Electrode Electrochemical Cell at Various Boundary Conditions at Anodes

Abstract

The frequency dependence of the transfer function of an electrochemical cell is studied experimentally and theoretically in the frequency region 0.005 to 1 Hz under conditions of controlled convective diffusion, at various boundary conditions on the anodes. It is shown that the results are independent of the conditions on the anodes at frequencies exceeding a diffusion frequency. On the other hand, the effect of the boundary conditions al low frequencies is substantial. In particular, it is shown that it is feasible to design a cell with a conversion efficiency indefinitely increasing in the direction of lower frequencies.

The fabrication of electrochemical geophone based on FPCB process technology

“…Similar with the previous studies [2][3][4][5][6], schematic depiction of electrochemical geophone is shown in Fig. 1.…”

“…Electrochemical motion sensor substantially originated from 1990s, which should be attributed to the continuous research work from V. A. Kozlov and V. M. Agafonov et al [2][3][4][5][6][7] The practical advantage of the electrochemical motion sensor is the ability for providing a high conversion factor with a very simple and suitable mass production signal converting system [7], which makes it possible for increasing the bandwidth by the mean of signal process or feedback control technology although the sensitivity for motion will be lost a little. So, there is a great potential for electrochemical motion sensor designed as geophone.…”

The influence of the boundary condition on anodes for solution of convection–diffusion equation with the application to a four-electrode electrochemical cell

“…Four-electrode electrochemical cells comprised of two symmetrically placed anodes and cathodes and filled up with a potassium iodide-iodine aqueous electrolyte have been used as the sensing element in motion sensors [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. In such electrochemical cells, to provide enough electric conductivity in the bulk electrolyte so that the electric potential drop is confined within the thin electrical double layer (EDL) right next to the electrodes, the iodide concentration is usually much larger than that of the tri-iodide, which serves as the active ion determining the limiting current at the cathode.…”

“…In such electrochemical cells, to provide enough electric conductivity in the bulk electrolyte so that the electric potential drop is confined within the thin electrical double layer (EDL) right next to the electrodes, the iodide concentration is usually much larger than that of the tri-iodide, which serves as the active ion determining the limiting current at the cathode. The fact that the electric field is negligible in the bulk electrolyte makes the convection-diffusion equation the most common approach to theoretically describe the transport phenomena in such electrochemical cells [1][2][3][4][5][6][9][10][11]16,17]. In the convection-diffusion model, either only the active component, i.e., tri-iodide, is considered [1][2][3][4][5][6][9][10][11], or all three species of ions are included with some approximations [16,17].…”

“…The fact that the electric field is negligible in the bulk electrolyte makes the convection-diffusion equation the most common approach to theoretically describe the transport phenomena in such electrochemical cells [1][2][3][4][5][6][9][10][11]16,17]. In the convection-diffusion model, either only the active component, i.e., tri-iodide, is considered [1][2][3][4][5][6][9][10][11], or all three species of ions are included with some approximations [16,17]. The obvious advantage of the convection-diffusion approach is the significantly simplified mathematical formulation, which makes analytical solutions available in some cases [1,2,4,6,[9][10][11] and requires much less computational resources for numerical simulations [3,5,16,17].…”