Flexible Lithium-Ion Fiber Battery by the Regular Stacking of Two-Dimensional Titanium Oxide Nanosheets Hybridized with Reduced Graphene Oxide

Increasing interest has recently been devoted to developing small, rapid, and portable electronic devices; thus, it is becoming critically important to provide matching light and flexible energy-storage systems to power them. To this end, compared with the inevitable drawbacks of being bulky, heavy, and rigid for traditional planar sandwiched structures, linear fiber-shaped lithium-ion batteries (LIB) have become increasingly important owing to their combined superiorities of miniaturization, adaptability, and weavability, the progress of which being heavily dependent on the development:of new fiber shaped electrodes. Here, we report a novel fiber battery electrode based onilie most widely used LIB material, titanium oxide, which is processed into two-dimensional nanosheets and assembled into a macroscopicfiber by a scalable wet-spinning process. The titania sheets are regularly stacked and conforrnally-hybridized in situ with reduced graphone oxide (rGO), thereby serving as,efficient current collectors, which endows the novel fiber electrode with. excellent integrated-meclianical properties combined with superior battery performances hi terms of linear densities, rate capabilities, and,cyclic behavior. The present study clearly cIenionstrates a new material-design paradigm toward novel fiber electrodes by assembling metal oxide nanosheets into an ordered macroscopic structure, which would represent the most-promising Solution to advanced flexible energy-storage systems.