Relevant fundamentals of the electrochemical double layer and supercapacitors utilizing the interfacial capacitance as well as superficial redox processes at the electrode/solution interface are briefly reviewed. Experimental methods for the determination of the capacity of electrochemical double layers, of charge storage electrode materials for supercapacitors, and of supercapacitors are discussed and compared. Intrinsic limitations and pitfalls are indicated; popular errors, misconceptions, and mistakes are evaluated. The suitability of available methods is discussed, and practical recommendations are provided.

The corrosion susceptibility of a selection of amalgams used in dentistry has been examined with the electrochemical impedance method. The results are compared with data derived from cyclic voltammetry performed with these materials before. Most examined materials including a conventional amalgam show similar corrosion resistance; however, only one product shows a significantly higher corrosion resistance.

Zusammenfassung: In Lehre wie Forschung ist die Wasserstoffbezugselektrode unerlässlich. Da sie in klassischer Ausführung den Gebrauch von Druckwasserstoff erfordert, ist ihre praktische Nutzung potentiell eingeschränkt. Ausgehend von einem Konzept einer vorgeschlagenen Wasserstoffbezugselektrode, die ohne Druckwasserstoff auskommt und dennoch alle Vorteile der konventionellen Wasserstoffbezugselektrode aufweist, wird aufgezeigt, dass diese Elektrode für gängige Praktikumsversuche ebenso korrekte Resultate zugänglich macht. Stichworte: Wasserstoffelektrode • Bezugselektrode • GaselektrodeMeasurements with a hydrogen electrode without pressured gas

A reference electrode is a half-cell (an electrode) with a stable, well-defined and highly reproducible electrode potential. A vast number of electrodes have been developed for different applications. They are briefly presented. For the common types, the advantages and drawbacks are discussed. Practical hints for daily use are provided.

Both thermodynamic and kinetic corrosion process parameters are determined with electrochemical methods. Results are used for a deeper understanding of the established interfacial structures and ongoing processes and of the effects of experimental parameters. Frequently data are used for the evaluation of corrosion inhibitor efficiencies. In case data from just one electrochemical method are used, the validity of the method and data should be verified and critical points must be identified. In this study, we have compared results from three standard electrochemical methods obtained with a common steel sample in an acidic environment and in the presence of three representative aromatic inhibitors. We have noticed significant differences between the results; therefore we suggest rationalization and practical consequences.