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

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.