Progress in solvent-free dry-film technology for batteries and supercapacitors

Solvent-free dry-film technology has attracted wide attention due to its ability to avoid pollution/waste caused by poisonous organic solvents, as well as its advantage for energy density enhancement, electrochemical performance improvement and electrode–electrolyte interface compatibility. However, a summary of the research advancements and technology development in this field is still missing. To fill this gap, a complete overview of the technical advantages, development process, principal mechanisms and application fields of solvent-free dry film technology is presented here. Firstly, the history of solvent-free dry-film technology is introduced, followed by detailed discussions on different types of dry-film making methods. Moreover, powder spray and binder fibrillation are emphasized as key methods due to their low-cost mass-production capability, with an elaboration on the associated preparation process including principle, procedure, and parameters. Both patents from the industry and research papers from the academy of the aforementioned two methods are analyzed/summarized for complete information, whose technical advantages are found to be suitable for all solid-state batteries (ASSBs). Based on the insights obtained above, perspectives are given for promoting future development of solvent-free dry-film technology.