Multiphysics simulations of cyclic voltammetry response of flexible screen-printed electrodes for wearable sensing systems

This work presents a novel multiphysics model for simulating the cyclic voltammetry (CV) response of flexible screen-printed electrodes (SPEs). Four different carbon SPEs geometric layouts, fabricated onto flexible PET substates, are studied through simulations to aid the choice of the best electrode configuration for wearable sensing systems. Our comprehensive and versatile model is based on the 3D structures of the devices under examination considering the main electrochemical phenomena at the metal/solution interface, the potentials, the ionic and electronic currents, and the measurement set-up. The model is first calibrated through a dedicated set of experimental CV and impedance spectroscopy measurements on the SPE devices under examination with 5 mM ferri/ferrocyanide redox couple in 0.1 M potassium chloride. The calibrated model is used to predict the expected CV response of four different layouts. The simulated curves report more than 80% higher current peaks than the experimental results, suggesting the presence of surface defects lowering the currents in real devices. The expected performances of the layouts are compared through simulation of the electrolyte current density, discussing the influence of different electrode areas and distances.