Reproducing capacitive cyclic voltammetric curves by simulation: When are simplified geometries appropriate?

The usage of multi-physics simulation tools is steadily increasing in the field of electrochemistry. While this is a great opportunity for closing the gap between analytical electrochemists used to simple 1D models and exper-imentalists, there are possible pitfalls that must be avoided. In this work, we raise awareness on numerical ar-tifacts that can mislead the interpretation of cyclic voltammetry experiments through simulations of geometries with different number of spatial dimensions. In particular, we show that one-dimensional simulations can suffer from substantial errors when models go beyond charge neutrality assumption. We exemplify such situations using simple electrolyte/electrode structures with 1D, 2D and 3D geometries. We then show the occurrence of artifacts related to the geometry of the simulation domain on the simulation of cyclic voltammetric curves as those typically performed to characterize conjugated polymer/electrolyte blends. All the models are imple-mented using COMSOL Multiphysics and are accompanied by a detailed description of their implementation. However, geometrical artifacts identified in this work also apply to other simulation approaches.