Electrochemical Fixation of Carbon Dioxide in Molten Salts on Liquid Zinc Cathode to Zinc@Graphitic Carbon Spheres for Enhanced Energy Storage

Fixation of carbon dioxide into advanced energy materials is an ideal protocol to address challenges in energy and environmental sustainability, with the efficiency of CO 2 fixation and the functionality of derived materials being the key-enabling factors. Herein, using a liquid zinc cathode for CO 2 fixation in molten salts, CO 2 is electrochemically converted to graphitic carbon shells over spherical Zn cores, namely, Zn@C. The liquid Zn serves as a depolarizer to facilitate the reduction of CO 2 , and also a soft template to direct the generation of core–shell Zn@C spheres. Density functional theory calculations reveal that the coexisting Zn can enlarge the interlayer gap of graphitic carbon and induce a strong electronic interaction with AlCl 4 − . Such a strong coupling between Zn and carbon hence offers an enhanced energy storage capability of the Zn@C. The present study provides suggestions for enhancing efficiency of CO 2 fixation and value-added utilization of nonferrous metals.