Preparation of microporous cu foam structure by electrodeposition, and its application to Li-ion battery

Abstract

This study deals with the manufacturing method of microporous copper foam film with 3-dimensionally interconnected, open network of pores. Microporous metallic foam structures have been extending their application in the fields of electrochemical devices, owing to their high specific surface area. However, most of these structures were composed of the isolated pores aligned perpendicular to the substrate surface, which hardly allow the lateral transport of reacting species. But in this study, the preparation of copper foam structure which had open network of 3-dimensionally interconnected pores and allowed easier lateral transport was successfully achieved by simple electrodeposition process. This open-celled foam structure is similar to the polymeric foam, but a unique one which has never been reported by electrodeposition technique. Therefore, it is expected that the suggested methodology in this study can contribute to most of research focused on the manufacturing of microporous foam structure and its utilization to electrochemical devices. This highly porous copper foam with 3-dimensionally interconnected pores was made by an electrodeposition technique utilizing hydrogen bubbles, generated concurrently with copper deposition, as templates for forming spherical pores. In the electrodeposition process, each deposit exhibited a characteristic morphology, such as open-celled foam or closed-celled foam, depending on the deposition parameters such as bath composition, additive and current density. In order to improve the porosity and robustness of copper foam foil, ammonium ion, chloride ion, polyethylene glycol (PEG), and 3-mercapto-1-propane sulfonic acid, sodium salt (MPSA) were introduced as additives into the electrodeposition bath, and their effects at extremely high cathodic polarization were investigated in this study. These chemical additives in electrodeposition bath had influence on the morphology (or porosity) and strength of copper foam e...