Cauliflower-Like Ni/MXene-Bridged Fiber-Shaped Electrode for Flexible Microsupercapacitor

Microscale, flexible, and lightweight electrodes are of interest for the generation of light and miniaturized energy storage systems such as microsupercapacitors. Wire or fiber-shaped electrodes can be considered as potential candidates for microsupercapacitor fabrication. Herein, a facile strategy for the preparation of high electrochemical performance fiber-shaped microsupercapacitors based on Ni(OH)(2)-Ni-Ti3C2 film on a copper wire (CW) electrode is presented. We employed a porous cauliflower-like Ni-Ti3C2 MXene film as the supporting scaffold to bridge a Ni(OH)(2) active substance with a Cu wire current collector. This hierarchical structure supplies a high surface area, many electroactive sites, and a short ion diffusion pathway and delivers outstanding performance with superior capacitance (1725.23 Fcm(-3) and 19.81 Fcm(-2) at 4 mAcm(2)) and a rather high rate capability (929.23 Fcm(-3) and 10.33 Fcm(-2) at 20 mAcm(-2)). It should be noted that the electrochemical behavior of Ni-Ti3C2@CW is significantly better than that of directly growing Ni on Cu wire due to the cauliflower-like morphology and high conductivity of the Ti3C2. Furthermore, a fiber-shaped supercapacitor (FSC) is assembled using Ni(OH)(2)-Ni-Ti3C2@CW and Ti3C2@CW as the positive and negative electrodes, respectively. The fabricated FSC shows high capacitance (72.35 Fcm(-3) and 756 mFcm(-2) at 1.5 mAcm(-2)), good rate capability, a maximum energy density of 206 mu Whcm(-2) at a power density of 1.94 mW cm(-2), long cycling stability (89.3% capacitance retention after 7000 cycles at 50 mVs(-1)), and good flexibility. Therefore, the introduced wire-shaped electrode through a simple process could be a promising approach for a new class of microsupercapacitors.