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.

All-Printed High-Performance Flexible Supercapacitors Using Hierarchical Porous Nickel–Cobalt Hydroxide Inks

“…6−8 However, the development of high-performance flexible supercapacitors still faces many difficulties, such as low energy density, poor rate performance, and the high cost of large-scale production. 9−11 In contrast to the current commercial carbonbased electrode materials, 12,13 transition metal oxides/hydroxides exhibit higher theoretical capacitance values, 14−17 which help to make up for the low energy density of existing supercapacitors. 18−24 However, the problems such as poor conductivity, inferior reversibility, and slow redox kinetics of transition metal oxides/hydroxides often lead to unsatisfied capacity and rate performance.…”

Facile Synthesis of Ternary Mn/Ni/Co Oxides as Bifunctional Energy Storage Materials for High-Performance Asymmetric Supercapacitors and Aqueous Zinc-Ion Batteries

“…Recently, ionic liquids (ILs), which are organic salts possessing a melting point lower than room temperature, have attracted the mass attention of researchers due to their advantages of high thermal stability, low vapor pressure, and wide voltage window . One of the typical ILs is 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF 4 ), which is composed of 1-ethyl-3-methylimidazolium (EMIM) for cations and tetrafluoroborate (BF 4 ) for anions . EMIMBF 4 as the electrolyte could maximize the working potential of SCs up to 4.0 V, endowing an obvious enhancement of energy density and relatively high ion conductivity for SCs .…”

“…15 One of the typical ILs is 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF 4 ), which is composed of 1-ethyl-3-methylimidazolium (EMIM) for cations and tetrafluoroborate (BF 4 ) for anions. 16 EMIMBF 4 as the electrolyte could maximize the working potential of SCs up to 4.0 V, endowing an obvious enhancement of energy density and relatively high ion conductivity for SCs. 17 Hence, fabricating ASCs with EMIMBF 4 electrolyte to obtain increased energy density is a seductive method for facing the challenges in the study of SCs.…”

In Situ Growth of Oriented Polyaniline Nanorod Arrays on the Graphite Flake for High-Performance Supercapacitors

“…13 Recently, carbon materials combining with PANI nanorods arrays have received extensive attention in the application of supercapacitors because of their low cost, good chemical stability, thermal stability, electrical conductivity, and mechanical properties. 18,19 For instance, Yu et al reported that the controllable PANI nanoarray could easily grow onto the surface of reduced graphene oxide nanosheets by chemical oxidation, and the prepared composite as an electrode material had a high specific capacitance (the specific capacitance is 752 F/g at 1 A/ g) and good cycle stability (the specific capacitance could retain 90.8% after 10,000 charge/discharge cycles). 20 Wu et al proposed a high-performance micro-supercapacitor based on a microfluid-oriented core-sheath PNA/graphene (PNA/G) composite fiber electrode.…”