Three-Electrode Reference Setup for Anode Overpotential Measurement
Three-electrode anode overpotential testing isolates uncompensated potential thresholds to prevent lithium plating during fast charge algorithm design
Uncompensated Resistance
Meaning
Electrochemical diagnostic evaluations must account for the portion of the internal cell resistance that sits between the reference electrode and the working electrode during measurements. This uncompensated resistance creates a voltage drop that is included in the raw measured potential, which distorts the recorded electrode voltage. Compensating for this value is essential for accurate determination of electrode kinetics.
Measurement Technique
Determination of this resistance value is typically achieved using high-frequency electrochemical impedance spectroscopy or current interrupt methods. The instrument measures the resistance at a frequency where the capacitive double-layer has not yet charged. Once identified, the software can correct the applied potential in real-time.
Diagnostic Significance
Highly accurate voltage readings are important when analyzing the onset of side reactions like lithium plating or electrolyte decomposition. If the uncompensated resistance is left uncorrected, the recorded anode potential will appear higher or lower than its true value. This error can lead to incorrect conclusions about cell safety limits, which might cause engineers to configure the charging algorithm too aggressively.
System Boundary
Physical placement of the reference electrode determines the magnitude of this resistance, with closer positioning reducing it. However, placing the reference too close can shield the working electrode and distort the current distribution. Designers must balance these factors during setup.