High-quality single-walled carbon nanotube films as current collectors for flexible supercapacitors

Current collectors with light weight, excellent durability, and mechanical robustness are highly demanded for flexible energy storage devices. Here, we prepare free-standing single-walled carbon nanotube films (SWCNFs) with a three-dimensional interconnected porous structure via floating catalyst chemical vapor deposition and apply them as current collectors for flexible supercapacitors. These SWCNFs present high mass loading efficiency, outstanding mechanical robustness, and excellent anti-corrosion properties, showing distinct advantages over conventional metal foil current collectors. The loading efficiency is up to 75% for pseudocapacitive cobalt(ii) carbonate hydroxide materials, exhibiting superior electrochemical performance in terms of specific capacitance, rate capability, and cycling performance. In addition, the assembled hybrid supercapacitors (SWCNF-cobalt carbonate hydroxide//SWCNF-polyaniline) exhibit outstanding flexibility under various bending deformations and long-term stability. Free-standing SWCNFs have proven to be promising candidates for ultralight current collectors for flexible supercapacitors.