Efficient Energy Conversion and Storage Based on Robust Fluoride‐Free Self‐Assembled 1D Niobium Carbide in 3D Nanowire Network

Owing to their high robustness and conductivity, 2D transition metal carbides and nitrides known as MXenes are considered as a promising material class for electrochemical catalysis, energy conversion, and storage applications. Nevertheless, conventional hazardous fluoride‐based synthesis routes and the intense intralayer bonding restrict the development of MXenes. Herein, a fluoride‐free, facile, and rapid method for synthesizing self‐assembled 1D architecture from an MXene‐based compound is reported. The MXene nanowire (NW) not only provides a robust connection to the flexible substrate but also effectively increases the electrochemically active surface area. The kinetics‐favorable structure yields a boosted performance for the hydrogen/oxygen evolution reaction and the intake of the zinc ion. The 1D NW based on MXene compound maintains high stability in a quite low overpotential of 236 mV for 24 h without detachment from the substrate and manifests an exceptional high‐power density of 420 W kg−1 over 150 cycles as a flexible aqueous zinc ion battery. This work paves a novel and non‐toxic synthesis method for the 1D nanofiber structure from MXene composition and demonstrates its multifunctional applications for energy conversion and storage. With the facile technique in alkali hydrolysis and HF‐free electrochemical etching, MXene nanowire is fabricated in a shortened etching time without the utilization of hazardous HF acid. The MXene NW@3D substrate not only renders a boosted kinetics and shortened diffusion length, but also offers a stable hydrogen evolution activity and flexible zinc ion battery application even during the deformation progress.