Microplasma Anode Meeting Molten Salt Electrochemistry: Charge Transfer and Atomic Emission Spectral Analysis

Molten salt electrolysis is normally conducted with solid anode, such as noble metal or graphite, which has defects such as high cost or emission of carbon oxide. Herein, we report that a microplasma based on atmospheric-pressure glow discharge could act as a kind of gaseous anode for electrolysis in molten salt. When the Ag/Ag⁺ redox couple was chosen as the research object, the microplasma anode could initiate charge-transfer reactions in the molten salt and Ag could be electrodeposited with current efficiency of above 90%. The microplasma anode has also shown excellent anticorrosive performance in both chloride and carbonate molten salt. Furthermore, the microplasma anode could potentially serve as an excitation source of atomic emission spectrometry (AES), making it possible to determine the concentration of Ag ions in the molten salt in situ and in real-time. With properties such as being carbon-free and having corrosion resistance and extensive utilization for analysis, the microplasma anode has opened a new direction for molten salt electrochemistry.