Numerical Resolving of Net Faradaic Current in Fast-Scan Cyclic Voltammetry Considering Induced Charging Currents

Area of Science:

• Electrochemistry
• Analytical Chemistry

Background:

• Fast-scan cyclic voltammetry (FSCV) is sensitive to current contributions.
• Induced charging currents arise from coupled faradaic and capacitive currents with uncompensated resistance.
• These currents alter the capacitive contribution compared to measurements without electroactive species.

Purpose of the Study:

• To theoretically and experimentally investigate induced charging currents in FSCV.
• To address the inaccuracy of conventional background subtraction methods in specific conditions.
• To develop and validate a novel method for separating faradaic and capacitive currents.

Main Methods:

• Theoretical modeling of induced charging currents.
• Experimental validation using potassium ferrocyanide/ferricyanide redox couple.
• Utilizing platinum disk electrodes and varying NaClO4 concentrations for different cell time constants.

Main Results:

• Induced charging currents significantly impact FSCV, especially when capacitive current is close to the total current.
• Conventional background subtraction methods can be inaccurate under these conditions.
• The developed method successfully separates faradaic and capacitive currents, even with potential-dependent capacitance.

Conclusions:

• The proposed method accurately quantifies capacitive currents in FSCV, overcoming limitations of traditional approaches.
• This advancement is crucial for precise electrochemical analysis in systems with significant capacitive contributions.
• The study provides a more reliable approach for interpreting FSCV data.