Studies on electrochemical CO2 conversion systems that can be used to obtain useful chemicals through conventional petrochemical processes while eliminating CO2, without polluting the environment, are essential for creating a carbon-neutral society. While significant progress has been made through a number of relevant studies, they have only been laboratory-scale in size so far. In fact, there are still many roadblocks to industrial application, such as the scaling up and development of suitable catalysts and electrodes.