Advances in electrolytic copper foils: fabrication, microstructure, and mechanical properties

Electrolytic copper foil has gained significant attention as an essential component in lithium-ion batteries (LIBs), printed circuit boards (PCBs), and chip packaging substrates (CPSs) applications. With the advancement of LIBs towards higher energy densities and the increasing density of electronic components on circuits, copper foil is required to have demanding properties, such as extremely thin thickness and extremely high tensile strength. This comprehensive review firstly summarizes recent progress on the fabrication of electrolytic copper foil, and the effects of process parameters, cathode substrate, and additives on the electrodeposition behavior, microstructure, and properties of copper foil are discussed in detail. Then the regulation strategies of mechanical properties of electrolytic copper foil are also summarized, including the formation of nanotwins and texture. Furthermore, the recent advances in novel electrolytic copper foils, such as composite foils and extra-thin copper foils, are also overviewed. Lastly, the remaining challenges and perspectives on the further development of electrolytic copper foils are presented.