Knittable energy storing fiber with high volumetric performance made from predominantly MXene nanosheets

A new member of the 2D family called MXene offers metallic conductivity and outstanding electrochemical properties that are important for developing fiber supercapacitors. To date, however, scalable approaches for preparing MXene-based fibres have been relatively unexplored. Here we demonstrate that a graphene oxide liquid crystal-assisted fiber spinning approach can be used to produce novel fibers that are predominantly MXene by weight (similar to 88 wt%). These MXene fibers exhibit high volumetric capacitance (similar to 341 F cm (3)) and electrical conductivity (similar to 72.3 S cm(-1)) and excellent strength and flexibility that allow knitting of MXene-based textile prototypes. The supercapacitor device made from MXene fibers displays excellent stability after 20 000 cycles and delivers maximum energy and power densities of similar to 5.1 mW h cm(-3) and similar to 1700 mW cm(-3), respectively. This work introduces a new class of fiber supercapacitors that offer great potential for realizing flexible power sources for miniaturized electronic gadgets and wearable technologies.