Language
Country/Area
No result found
Did you know what the challenges are with reference electrodes in non-aqueous systems?
In electrochemical research, reference electrodes play a vital role. It is an electrode with a stable and known electrode potential that provides a baseline for measuring other electrodes in the battery. Although common reference electrodes such as standard hydrogen electrodes (SHE) perform stably in aqueous systems, there are many challenges in their use in non-aqueous systems.
Traditional aqueous reference electrodes such as saturated Caromel electrodes (SCE) and silver silver chloride electrodes (Ag/AgCl) rely on saturated aqueous solutions, which makes their performance unreliable in non-aqueous systems.
First, non-aqueous substances such as amide or alcohol can adversely affect the performance of the reference electrode. For example, the metal electrode of a standard hydrogen electrode is quickly poisoned in certain solvents, causing the potential to become unstable and greatly reducing its reliability as a reference. In some cases, even short-term use of aqueous reference electrodes can have unpredictable effects because their contact with non-aqueous solvents can form a liquid-liquid interface and introduce interfacial potential differences that are difficult to measure.
The biggest problem with using an aqueous reference electrode is that potential measurements in different solvents are not comparable, making potential problems that make these measurements unreliable.
In order to solve these problems, the concept of quasi-reference electrode (QRE) has been introduced in recent years. The quasi-reference electrode can use ferrocene or other internal reference materials to make it more stable in non-aqueous environments. The fabrication process of these electrodes is also relatively simple and can be remade before each experiment, which is crucial for the reliability of the experiment.
The simplicity of the production process of the quasi-reference electrode allows for softer conditions and settings to ensure the reliability of the reference in the new round of experiments.
However, quasi-reference electrodes are not perfect. Their stability again depends on the known conditions of the environment in which they are composed. For example, if you want to use a perovskite electrode as a reference, you must be aware of changes in pH and other environmental variables, otherwise its measurements will be interfered with.
Another challenge arises from the so-called "pseudo reference electrodes", whose potential is not stable but changes under different experimental conditions. Therefore, although they can be used under known conditions, their outcomes are less predictable in environments with higher uncertainty. This type of electrode is mainly used in certain specific research fields, such as the development of zirconium nitride (YSZ) membrane electrodes. Its potential changes according to the pH value of the experiment, and its application at high temperatures is even more significant.
Reference electrode challenges in non-aqueous systems are not limited to stability issues, but also include reduction of experimental error and transparency of results. These challenges require researchers to be more careful in experimental design to fundamentally address the limitations of these electrodes compared to aqueous systems. While pursuing high accuracy in studying electrochemical processes, how to overcome these challenges is an important issue in the future.
Whether it is possible to successfully develop a stable and reliable non-aqueous system reference electrode without using an aqueous reference will become the key to promoting the development of electrochemical technology?
