Overview of CO2 capture and electrolysis technology in molten salts: operational parameters and their effects

Abstract

Carbon capture and storage (CCS) technology is believed to be a promising solution for global CO₂ emission control and climate change. However, the application of CCS projects is facing a dilemma due to their negative cash flow. To address the challenge, it is critical to adopt an innovative technology that can capture and convert CO₂ simultaneously with satisfying efficiencies and can make a profit for the end users. Recently, molten salt CO₂ electrolysis that splits CO₂ into carbon and oxygen has been extensively studied. This study reviews the process mechanisms, the salt selection, and the effects of operating conditions, including temperature and voltage. In most reported articles, the CO₂ to carbon conversion efficiency reached at least 80%, and the current efficiency is over 90%, proving the promising potential of the molten salt CO₂ electrolysis method. Still, some aspects, such as the impurities' influences and electrode corrosion, have not been thoroughly investigated. Therefore, some suggestions are recommended for future work.

Keywords: CO₂ capture; CO₂ conversion; Molten salt CO₂ electrolysis; CO₂ reduction; Carbon nanotubes.