High specific surface area MXene/SWCNT/cellulose nanofiber aerogel film as an electrode for flexible supercapacitors

Transition metal carbonitrides (MXene) with two-dimensional layered structures are a recent research topic in the field of supercapacitors. However, because MXene can easily self-stack, its capacitance performance is affected. To this end, one-dimensional cellulose nanofibers (CNF) and carboxylic single-walled carbon nanotubes (SWCNT) were used to intercalate MXene to obtain well-dispersed MXene/SWCNT/CNF aqueous suspensions and their hybrid hydrogels, and to obtain hybrid aerogels through supercritical drying. CNF gives aerogel excellent porosity, a high specific surface area (301.03 m2 g-1), good electrolyte infiltration, and gentle me-chanical flexibility, while SWCNT imparts high conductivity to aerogel film. We assembled a symmetrical all -solid-state flexible supercapacitor and interdigitated micro-supercapacitors using an aerogel film as a flexible electrode. The area specific capacity of the above electrode reaches 746.68 mF cm-2 and 244.50 mF cm-2, respectively. This study provides a fabrication method of polymer-inorganic hybrid nanocomposite aerogel film electrodes for flexible supercapacitors.

Automated summary

Transition metal carbonitrides (MXene) have gained attention in the supercapacitor field due to their two-dimensional layered structure. However, their performance is affected by self-stacking. To address this issue, researchers used one-dimensional cellulose nanofibers (CNF) and carboxylic single-walled carbon nanotubes (SWCNT) to intercalate MXene, resulting in well-dispersed MXene/SWCNT/CNF aqueous suspensions and hybrid hydrogels. These hydrogels were then transformed into hybrid aerogels through supercritical drying. The CNF provided excellent porosity, high specific surface area (301.03 m2 g-1), good electrolyte infiltration, and mechanical flexibility, while the SWCNT contributed to high conductivity in the aerogel film. The researchers successfully assembled a symmetrical all-solid-state flexible supercapacitor and interdigitated micro-supercapacitors using the aerogel film as a flexible electrode, achieving area specific capacities of 746.68 mF cm-2 and 244.50 mF cm-2, respectively. This study presents a fabrication method for polymer-inorganic hybrid nanocomposite aerogel film electrodes for flexible supercapacitors.