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 (335.8â µWh cm-2 ) and large areal capacitance (2760â 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.
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.
ABSTRACT
Advanced methods, allowing the controllable synthesis of ordered structural nanomaterials with favourable charges transfer and storage, are highly important to achieve ideal supercapacitors with high energy density. Herein, we report a microliter droplet-based method to synthesize hierarchical-structured metal-organic framework/graphene/carbon nanotubes hybrids. The confined ultra-small-volume reaction, give well-defined hybrids with a large specific-surface-area (1206â m2 g-1 ), abundant ionic-channels (narrow pore of 0.86â nm), and nitrogen active-sites (10.63 %), resulting in high pore-size utilization (97.9 %) and redox-activity (32.3 %). We also propose a scalable microfluidic-blow-spinning method to consecutively generate nanofibre-based flexible supercapacitor electrodes with striking flexibility and mechanical strength. The supercapacitors display large volumetric energy density (147.5â mWh cm-3 ), high specific capacitance (472â F cm-3 ) and stably deformable energy-supply.
ABSTRACT
Photonic crystals (PCs) have been widely applied in optical, energy, and biological fields owing to their periodic crystal structure. However, the major challenges are easy cracking and poor structural color, seriously hindering their practical applications. Now, hydrophobic poly(tert-butyl acrylate) (P(t-BA)) PCs have been developed with relatively lower glass transition temperature (Tg ), large crack-free area, excellent hydrophobic properties, and brilliant structure color. This method based on hydrophobic groups (tertiary butyl groups) provides a reference for designing new kinds of PCs via the monomers with relatively lower Tg . Moreover, the P(t-BA) PCs film were applied as the photoluminescence (PL) enhanced film to enhance the PL intensity of CdSe@ZnS QDs by 10-fold in a liquid-crystal display (LCD) device. The new-type hydrophobic force assembled PCs may open an innovative avenue toward new-generation energy-saving devices.
ABSTRACT
Bioinspired methods allowing artificial actuators to perform controllably are potentially important for various principles and may offer fundamental insight into chemistry and engineering. To date, the main challenges persist regarding the achievement of large deformation in fast response-time and potential-engineering applications in which electrode materials and structures limit ion diffusion and accumulation processes. Herein, a novel electrochemical actuator is developed that presents both higher electromechanical performances and biomimetic applications based on hierachically structured covalently bridged black phosphorous/carbon nanotubes. The new actuator demonstrates astonishing actuation properties, including low power consumption/strain (0.04 W cm-2 %-1 ), a large peak-to-peak strain (1.67%), a controlled frequency response (0.1-20 Hz), faster strain and stress rates (11.57% s-1 ; 28.48 MPa s-1 ), high power (29.11 kW m-3 ), and energy (8.48 kJ m-3 ) densities, and excellent cycling stability (500 000 cycles). More importantly, bioinspired applications such as artificial-claw, wings-vibrating, bionic-flower, and hand actuators have been realized. The key to high performances stems from hierachically structured materials with an ordered lamellar structure, large redox activity, and electrochemical capacitance (321.4 F g-1 ) for ions with smooth diffusion and flooding accommodation, which will guide substantial progress of next-generation electrochemical actuators.
