Challenge and technological trends of flexible solid-state supercapacitors

Flexible solid-state supercapacitors are wide application in flexible electronics due to low cost, facial fabrication, long cycling life, excellent safety and so on. As-well known, the performance of flexible solid-state supercapacitors strongly depends on structure and properties of its current collector, electrode and electrolyte. However, there are few works to simultaneously investigate the effect of current collector, electrode and electrolyte on performance of flexible solid-state supercapacitors. Here, the recent advances in flexible solid-state supercapacitors are summarized from design strategies to preparation, structure and properties of current collector, electrode and electrolyte. Especially, progress and challenge about current collector, free-standing electrode and gel electrolyte with anti-freezing, self-healing and self-discharging properties of flexible solid-state supercapacitors are also discussed in detail. Finally, we propose key research directions to design and prepare current collector, electrode and electrolyte for high-performance flexible solid-state supercapacitors. •Advance in current collector of flexible solid-state supercapacitors is discussed.•Free-standing electrode of flexible solid-state supercapacitors is reviewed.•Functional electrolyte of flexible solid-state supercapacitors is reviewed.