Hybrid capacitors exhibit promise to bridge the gap between rechargeable high-energy density batteries and high-power density supercapacitors. This separation is due to sluggish ion/electron diffusion and inferior structural stability of battery-type materials. Here, a topochemistry-driven method for constructing expanded 2D rhenium selenide intercalated by nitrogen-doped carbon hybrid (E-ReSe 2 @INC) with a strong-coupled interface and weak van der Waals forces, is proposed. X-ray absorption spectroscopy analysis dynamically tracks the transformation from ReO into ReC bonds. The bridging bonds act as electron transport channels to enable improved conductivity and accelerated reaction kinetics. The expanded interlayer-spacing of ReSe 2 layer by INC facilitates ion diffusion and ensures structural stability. As expected, the E-ReSe 2 @INC achieves an improved rate capability (252.5 mAh g −1 at 20 A g −1 ) and long-term cyclability (89.6% over 3500 cycles). Moreover, theoretical simulations reveal the favorable Na + storage kinetics can be ascribed to its low bonding energy of −0.06 eV and diffusion barrier of 0.08 eV for sodium ions. Additionally, it is demonstrated that 3D printed sodium-ion hybrid capacitors deliver high energies/power densities of 81.4 Wh kg −1 /0.32 mWh cm −2 and 9992.1 W kg −1 /38.76 mW cm −2 , as well as applicability in a wide temperature range.
Hierarchical SiO(2)@γ-AlOOH (Boehmite) core/sheath fibers are fabricated based on a combination of electrospinning and hydrothermal reaction. γ-AlOOH (Boehmite) nanoplatelets are uniformly anchored on the surface of SiO(2) fibers, which significantly improves the adsorption efficiency of the SiO(2) fiber membrane for organic dyes and microorganisms. Compared to conventional nanoparticle adsorbents, the self-standing membrane thus prepared is highly flexible and easy to handle and retrieve, making it a promising material for water treatment. By virtue of electrospinning and a hydrothermal reaction, it provides possibilities to fabricate other functional fiber membranes with hierarchical structures, which can find potential applications in adsorption, catalysis, filtration, and other environmental remediation fields.
Stand-off Raman spectroscopy combines the superior advantages of both Raman spectroscopy and remote detection to retrieve molecular vibrational fingerprints of chemicals at inaccessible sites. However, it is currently restricted to the detection of pure solids and liquids and not widely applicable for dispersed molecules in air. Herein, we realize real-time stand-off SERS spectroscopy for remote and multiplex detection of atmospheric airborne species by integrating a long-range optic system with a 3D molecular trapping metal-organic framework (MOF)-integrated SERS platform. Formed via the self-assembly of Ag@MOF core-shell nanoparticles, our 3D plasmonic architecture exhibits micrometer-sized thick hotspot to allow active sorption and rapid detection of aerosols, gas and volatile organic compounds down to parts-per-billion level, notably up to 10 meters. The platform is also highly sensitive to changes in atmospheric content as demonstrated in the temporal monitoring of gaseous CO2 in several cycles. Importantly, we demonstrate the remote and multiplex quantification of polycyclic aromatic hydrocarbons (PAH) mixtures in real-time under outdoor daylight. By overcoming core challenges in current remote Raman spectroscopy, our strategy creates enormous opportunity in the long-distance and sensitive monitoring of air/gaseous environment at the molecular level, especially important in environmental conservation, disaster prevention and homeland defense.
The use of free-standing carbon-based hybrids plays a crucial role to help fulfil ever-increasing energy storage demands, but is greatly hindered by the limited number of active sites for fast charge adsorption/desorption processes. Herein, an efficient strategy is demonstrated for making defect-rich bismuth sulfides in combination with surface nitrogen-doped carbon nanofibers (dr-Bi S /S-NCNF) as flexible free-standing electrodes for asymmetric supercapacitors. The dr-Bi S /S-NCNF composite exhibits superior electrochemical performances with an enhanced specific capacitance of 466 F g at a discharge current density of 1 A g . The high performance of dr-Bi S /S-NCNF electrodes originates from its hierarchical structure of nitrogen-doped carbon nanofibers with well-anchored defect-rich bismuth sulfides nanostructures. As modeled by density functional theory calculation, the dr-Bi S /S-NCNF electrodes exhibit a reduced OH adsorption energy of -3.15 eV, compared with that (-3.06 eV) of defect-free bismuth sulfides/surface nitrogen-doped carbon nanofiber (df-Bi S /S-NCNF). An asymmetric supercapacitor is further fabricated by utilizing dr-Bi S /S-NCNF hybrid as the negative electrode and S-NCNF as the positive electrode. This composite exhibits a high energy density of 22.2 Wh kg at a power density of 677.3 W kg . This work demonstrates a feasible strategy to construct advanced metal sulfide-based free-standing electrodes by incorporating defect-rich structures using surface engineering principles.
Carbon aerogel (CA) microlattices exhibits a controllable macrostructure by 3D printing as well as an interconnected porous microstructure from GP gel and presents a desirable areal and volumetric capacitance with high mass loading.
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