Rational Design of Interlocked Sandwich Structure for Freestanding Graphene‐Based Homogeneous Composite Fiber Electrode

ABSTRACT Freestanding graphene‐based composite fiber is generally assembled into a core‐sheath structure which suffers from limited loading mass and charge transfer processes. Herein, an interlocked sandwich structure is designed to develop freestanding graphene‐based homogeneous composite fiber and a novel compositing–assembling process is developed to realize the designed fiber. Firstly, polyaniline (PANI) is grown on graphene oxide (GO) sheets. The produced PANI/GO (PGO) composite is then assembled with individual GO sheets (GO′) to form GO′/PGO/GO′. The produced sandwich‐structured composite sheets are further interlocked together and reduced into G/PG/G (PGR) fiber. Benefiting from this rational structure design, the PANI loading mass achieves 41.6% and the charge transfer is significantly modified. Using it for supercapacitors, the specific capacitance of the PGR fiber electrode reaches 638.5 F g −1 at 1 A g −1 , and 375.9 F g −1 can be maintained at 10 A g −1 . Moreover, this freestanding homogeneous composite fiber electrode exhibits excellent flexibility. After bending with an angle of 180° for 10,000 cycles, 90.55% of the capacitance can be maintained.