Microfluidic‐Architected Nanoarrays/Porous Core–Shell Fibers toward Robust Micro‐Energy‐Storage

Abstract

Abstract Methods enabling the controllable fabrication of orderly structural and active nanomaterials, along with high‐speed ionic pathways for charge migration and storage are highly fundamental in fiber‐shaped micro‐supercapacitors (MSCs). However, due to fiber‐electrodes with compact internal microstructure and less porosity, MSCs usually display a low energy density. Here, an innovative microfluidic strategy is proposed to design ordered porous and anisotropic core–shell fibers based on nickel oxide arrays/graphene nanomaterials. Owing to the homogeneous microchannels reaction, the graphene core maintains a uniformly anisotropic porous structure, and the nickel oxide shell keeps steadily vertically aligned nanosheets. The MSC presents an ultrahigh energy density (120.3 µWh cm−2) and large specific capacitance (605.9 mF cm−2). This higher performance originates from the microfluidic‐architected core–shell fiber with abundant ionic channels (plentiful micro‐/mesopores), large specific‐surface‐area (425.6 m2 g−1), higher electrical conductivity (176.6 S cm−1), and sufficient redox activity, facilitating ions with quicker diffusion and greater accumulation. Considering those outstanding properties, a wearable self‐powered system, converting and storing solar energy into electric energy, is designed to light up displays. This microfluidic strategy offers an effective way to design new structural materials, which will advance the development of next‐generation wearable/smart industries.

Keywords

• fibers
• microfluidics
• micro‐supercapacitors
• nickel oxide arrays
• porous graphene