New App: Electrochemical Impedance Spectroscopy
Electrochemical impedance spectroscopy (EIS) is a common technique in electroanalysis. It is used to study the harmonic response of an electrochemical system. A small, sinusoidal variation is applied to the potential at the working electrode, and the resulting current is analyzed in the frequency domain.
The real and imaginary components of the impedance give information about the kinetic and mass transport properties of the cell, as well as the surface properties through the double layer capacitance.
The purpose of theElectrochemical Impedance Spectroscopy analysis app is to understand EIS, Nyquist, and Bode plots. The app lets you vary the bulk concentration, diffusion coefficient, exchange current density, double layer capacitance, and the maximum and minimum frequency.
New App: Cyclic Voltammetry
Cyclic voltammetry is a common analytical technique for investigating electrochemical systems. In this method, the potential difference between a working electrode and a reference electrode is swept linearly in time from a start potential to a vertex potential, and back again. The current-voltage waveform, called a voltammogram, provides information about the reactivity and mass transport properties of an electrolyte.
The purpose of the app is to demonstrate and simulate the use of cyclic voltammetry. You can vary the bulk concentration of both species, transport properties, kinetic parameters, and the settings of the cyclic voltammeter.
New Tutorial: Diffuse Double Layer
At the electrode-electrolyte interface, there is a thin layer of space charge, called the diffuse double layer. In this region, electroneutrality does not hold. The double layer may be of interest when modeling devices such as electrochemical supercapacitors and nanoelectrodes.
The Diffuse Double Layer tutorial shows you how to couple the Nernst-Planck equations to the Poisson equation in order to describe a diffuse double layer according to the Gouy-Chapman-Stern model.
The simulation app extends the simple example by including two electrodes. It also considers Faradaic (charge transfer) electrode reactions. An additional equation is solved to ensure overall conservation of charge.