Electrochemical research stretches across many different fields (as is evidenced by the numerous applications listed here). While many areas are distinct, there is often a great deal of overlap, especially in terms of some experimental techniques. “Physical Electrochemistry” is a bit of a catch-all term that actually covers many areas that are more fundamental in their research goals.
Physical electrochemistry includes theoretical and experimental aspects of double-layer structure, kinetic and mechanistic studies of heterogeneous electron transfer at electrode-electrolyte interfaces, electrocatalysis, and the application of spectroscopic and other techniques to the study of electrochemical interfaces and processes.
Ideally, researchers would take a full semester course on physical electrochemistry. If that isn't possible, knowledge of a few basics can assist you in your research. The principal experimental technique in physical electrochemistry is cyclic voltammetry (CV). CV is a linear scan of potential “out and back” with the measured current plotted vs potential. Scan rates can run from below 1 mV/s to more than 1000 V/s. At first glance, a CV gives a measure of the thermodynamics of an electron transfer (E0). It can be used analytically to solve for an unknown (diffusion coefficient, concentration, electrode area). More detailed analysis can lend insight into the kinetics, adsorbed/bound species, and can even yield mechanistic information.
Note that digital instruments approximate a linear sweep with a staircase, which is fine for diffusing species. Current resulting from bound species and capacitance, however, can be lost—though Gamry has a “Surface Mode” option that preserves/records all current passing through the electrode.
CV analysis, which has long been a combination of art and science, is best done today using simulation. Accurate models and a good simulation program are much better for studying complex systems. Basic information is available without simulation, but detailed information including rate parameters, adsorption isotherms, and chemical equilibria are not easily accessed outside of simulation.
Other techniques commonly used for research electrochemistry include pulse voltammetry, electrochemical impedance spectroscopy, chronoamperometry, chronocoulometry, and chronopotentiometry.
Electroanalytical chemistry is an expanding niche of physical electrochemistry. Traditional analytical electrochemistry was based around a wide range of pulse techniques. These techniques include differential pulse, square wave, normal pulse, various stripping techniques, and more. They can be incredibly sensitive, and are often better than cyclic voltammetry for getting analytical solutions.
Improvements in materials development are leading to greater interest in electrochemistry as a tool for sensing, particularly in life sciences. Here electroanalytical chemistry is meeting biochemistry with some impressive results. The most common electrochemical sensors around—glucose sensors—are used by millions of people everyday. Smaller electrodes, electrode arrays, more sensitive and faster potentiostats and electrochemical techniques like fast scan CV and EIS are continuing to revolutionize what is possible with electrochemistry.