ModuLab XM ECS: the Xtreme Measurement electrochemical test system
What is unique about ModuLab XM ECS?
ModuLab XM has modularity at the center of its design. Each system can be configured for electrochemical, materials, and photoelectrochemistry measurements. At the core of each of these is the Frequency Response Analyzer. The accuracy from design to calibration is at the heart of Solartron's success and reputation for impedance measurements.
Fast ADCs (40MHz) allow specialized techniques, such as Harmonic Analysis and Intermodulation at high sample rate to be performed at all frequencies; unlike sub-sampling techniques using slower ADCs common to other designs that are subject to aliasing errors. Harmonic Analysis is typically used to investigate cell non-linearity with application in fast charge / discharge of energy devices.
How does energy research benefit from this XM?
Standard features and available options such as high current boosters on ModuLab open the door to applications that other systems cannot achieve such as ultra-low, micro-ohm impedance cells (latest generation batteries and fuel cells, for example). Additional voltage measurements access simultaneous impedance measurements of the anode and cathode of a single cell; while high polarization voltage and high compliance voltage options use these for measuring across stacks of energy devices.
How is the Frequency Response Analyzer (FRA) used in Electrochemical Impedance Spectroscopy (EIS)?
The FRA interacts with the potentiostat, electrochemical cell , electrolyte solution to form an EIS instrumentation system. In EIS measurements, the signal is an AC sine wave on a DC background that is applied over a range of frequency. EIS data compares the applied signal-to-measured response and the result is the impedance magnitude and phase shift. These give rise to the real and imaginary portions of the impedance.
The most common representation of impedance data are the Nyqusit Plot sometimes called complex impedance plot. Nyquist Plot represents the real impedance on the X-axis and the imaginary component of the impedance on the Y-axis.
Different processes are represented as components in an equivalent circuit constructed of a number of circuit elements. This is based on their respective relationship with frequency. The Double Layer Capacitance is represented as a capacitor because the impedance varies inversely with frequency and all imaginary impedance. The Solution Resistance and Charge Transfer Resistance are represented as a resistor because their impedance is independent of frequency and all real impedance. The core building block of most equivalent circuits is the Randles cell, as it has these three key components: Double Layer Capacitance (electrical double layer), Solution Resistance, and Charge Transfer Resistance. Other components representing inductance and diffusion can be added to this to represent an appropriate circuit model for your test cell.
Impedance data aid in determination of State of Health SoH or State of Charge for Li-ion batteries, corrosion resistance or analyte concentration with impedance-based senors. EIS is the fastest growing technique in both applied and research electrochemistry.
Dedicated system for analysis of PhotoElectrochemistry and related applications.