Modeling cyclic voltammetry responses of porous electrodes: An approach incorporating faradaic and non-faradaic contributions through porous model and constant phase element

Abstract

Porous electrodes, with their complex structure and finite diffusion domain, present a challenge in interpreting cyclic voltammetry (CV) responses using conventional methods. Previous efforts have aimed to mitigate the impact of electrode structure on CV responses, employing various experimental and numerical strategies. In this study, a versatile porous model using the Bruggeman correlation to account for porosity and tortuosity effects on CV responses that can accurately simulate CV responses in porous electrodes without relying on pore-scale information was proposed and validated. This model was further extended to incorporate the effects of non-Faradaic currents. A thorough investigation of various parameters, including electrode thickness, porosity, Bruggeman exponent, reaction rate constant, and electrochemically active surface area, was conducted. This approach simplifies the required geometrical parameters to surface-to-volume ratio, electrode thickness, porosity, and Bruggeman exponent, reducing the reliance on pore-specific characteristics. This study presents an alternative approach to simulate CV responses in porous electrodes without the need for pore-scale information to strike a balance between complexity and practicality. The insights gained not only facilitate simpler modeling of porous electrodes but also enhance our understanding and characterization of CV responses in these systems. This knowledge is crucial for advancing the performance of electrochemical energy devices and marks a significant step towards a cleaner energy society.