Nonlinear Electrochemical Analysis: Worth the Effort to Reveal New Insights into Energy Materials

A variety of different methods for the investigation of electrochemical energy storage and conversion systems (e.g., batteries, fuel cells, and electrolyzers) and energy materials thereof are presented in the literature. But especially for scientists who are new to this field it is difficult to select methods that are appropriate for their research endeavors and to decide for the investment in these. In this overview, several starting points are given to facilitate this decision-making process. First, suitable operando methods (in particular Raman spectroscopy, X-ray diffraction, and online electrochemical mass spectrometry) are presented with a focus on their advantages and disadvantages. Subsequently, standard electrochemical methods are listed and their limits are given concerning their possible information level. Finally, with the nonlinear electrochemical methods, powerful techniques are introduced that mitigate the drawbacks of standard electrochemical and operando methods. In this regard, the versatile possibilities of these promising approaches are presented; present challenges are pointed out as well. Based on this, a possible future for the use nonlinear methods in the field of energy materials is derived.