Cyclic Voltammetry to Study Dynamics of Ion Insertion in Porous Materials
Résumé
Electrochemical charge storage in porous materials is associated with ion adsorption at the meso/nanopores surface (physical insertion) and/or insertion in the bulk material (chemical insertion). The first process is capacitive whereas the second is Faradaic. A model is brought about for describing the cyclic voltammetry responses of these systems and their dependence upon the various intrinsic and operational governing parameters. These responses may be considered as illustrating the behaviors expected in working conditions in terms of diagnosis of the main phenomena at work and of their mutual interactions, namely, dynamics of double-layer charging, transport in solution, transport in the pores, interfacial transfer kinetics, and transport in the material bulk. Several limiting cases are examined in detail and discussed, focusing on the effect of scan rate as a widely used diagnostic tool.