Magnetothermal Microfluidic‐Assisted Hierarchical Microfibers for Ultrahigh‐Energy‐Density Supercapacitors

Abstract Chemical architectures with an ordered porous backbone and high charge transfer are significant for fiber‐shaped supercapacitors (FSCs). However, owing to the sluggish ion kinetic diffusion and storage in compacted fibers, achieving high energy density remains a challenge. An innovative magnetothermal microfluidic method is now proposed to design hierarchical carbon polyhedrons/holey graphene (CP/HG) core–shell microfibers. Owing to highly magnetothermal etching and microfluidic reactions, the CP/HG fibers maintain an open inner‐linked ionic pathway, large specific surface area, and moderate nitrogen active site, facilitating more rapid ionic dynamic transportation and accommodation. The CP/HG FSCs show an ultrahigh energy density (335.8 μWh cm −2 ) and large areal capacitance (2760 mF cm −2 ). A self‐powered endurance application with the integration of chip‐based FSCs is designed to profoundly drive the durable motions of an electric car and walking robot.