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1.
Carbon-based electric double layer capacitors(EDLCs)hold tremendous potentials due to their high-power performance and excellent cycle stability.However,the practical use of EDLCs is limited by the low energy density in aqueous electrolyte and sluggish diffusion kinetics in organic or/and ionic liquids electrolyte.Herein,3D carbon frameworks(3DCFs)constructed by interconnected nanocages(10-20 nm)with an ultrathin wall of ca.2 nm have been fabricated,which possess high specific surface area,hierarchical porosity and good conductive network.After deoxidization,the deoxidized 3DCF(3DCFDO)exhibits a record low IR drop of 0.064 V at 100 A g^−1 and ultrafast charge/discharge rate up to 10 V s^−1.The related device can be charged up to 77.4%of its maximum capacitance in 0.65 s at 100 A g^−1 in 6 M KOH.It has been found that the 3DCF-DO has a great affinity to EMIMBF4,resulting in a high specific capacitance of 174 F g^−1 at 1 A g^−1,and a high energy density of 34 Wh kg^−1 at an ultrahigh power density of 150 kW kg^−1 at 4 V after a fast charge in 1.11 s.This work provides a facile fabrication of novel 3D carbon frameworks for supercapacitors with ultrafast charge/discharge rate and high energy-power density.  相似文献   

2.
Manganese oxides are regarded as one of the most promising cathode materials in rechargeable aqueous Zn-ion batteries(ZIBs)because of the low price and high security.However,the practical application of Mn2O3 in ZIBs is still plagued by the low specific capacity and poor rate capability.Herein,highly crystalline Mn2O3 materials with interconnected mesostructures and controllable pore sizes are obtained via a ligand-assisted self-assembly process and used as high-performance electrode materials for reversible aqueous ZIBs.The coordination degree between Mn2+and citric acid ligand plays a crucial role in the formation of the mesostructure,and the pore sizes can be easily tuned from 3.2 to 7.3 nm.Ascribed to the unique feature of nanoporous architectures,excellent zinc-storage performance can be achieved in ZIBs during charge/discharge processes.The Mn2O3 electrode exhibits high reversible capacity(233 mAh g−1 at 0.3 A g−1),superior rate capability(162 mAh g−1 retains at 3.08 A g−1)and remarkable cycling durability over 3000 cycles at a high current rate of 3.08 A g−1.Moreover,the corresponding electrode reaction mechanism is studied in depth according to a series of analytical methods.These results suggest that rational design of the nanoporous architecture for electrode materials can effectively improve the battery performance.  相似文献   

3.
Mn-based rechargeable aqueous zinc-ion batteries(ZIBs)are highly promising because of their high operating voltages,attractive energy densities,and eco-friendliness.However,the electrochemical performances of Mn-based cathodes usually suffer from their serious structure transformation upon charge/discharge cycling.Herein,we report a layered sodium-ion/crystal water co-intercalated Birnessite cathode with the formula of Na0.55Mn2O4·0.57H2O(NMOH)for high-performance aqueous ZIBs.A displacement/intercalation electrochemical mechanism was confirmed in the Mn-based cathode for the first time.Na+and crystal water enlarge the interlayer distance to enhance the insertion of Zn^2+,and some sodium ions are replaced with Zn^2+ in the first cycle to further stabilize the layered structure for subsequent reversible Zn^2+/H^+ insertion/extraction,resulting in exceptional specific capacities and satisfactory structural stabilities.Additionally,a pseudo-capacitance derived from the surface-adsorbed Na^+ also contributes to the electrochemical performances.The NMOH cathode not only delivers high reversible capacities of 389.8 and 87.1 mA h g^−1 at current densities of 200 and 1500 mA g^−1,respectively,but also maintains a good long-cycling performance of 201.6 mA h g^−1 at a high current density of 500 mA g^−1 after 400 cycles,which makes the NMOH cathode competitive for practical applications.  相似文献   

4.
In this paper, it presents the work which consists to develop and characterize a modified electrode with a conductive polymer film, poly [3-methyl thiophene] then incorporating manganese dioxide MnO2 into the film. The deposition of the polymer film on the surface of the glassy carbon electrode is realized by the electrochemical oxidation of the monomer [3-methyl thiophene] in an organic medium. Then the electrode obtained was immersed in a solution containing ions Mn4~ to introduce into the polymeric film. The technique of insertion of manganese ions is performed by interaction with the polymer film. The electrochemical oxidation of the modified electrode in an aqueous medium will precipitate the manganese dioxide in the form of particles in the polymer film. In this study, it was found that several parameters affect the amount of manganese dioxide introduced as the pH of the medium and the thickness of the polymer film.  相似文献   

5.
Huge volume changes of Si during lithiation/delithiation lead to regeneration of solid-electrolyte interphase(SEI)and consume electrolyte.In this article,γ-glycidoxypropyl trimethoxysilane(GOPS)was incorporated in Si/PEDOT:PSS electrodes to construct a flexible and conductive artificial SEI,effectively suppressing the consumption of electrolyte.The optimized electrode can maintain 1000 mAh g^−1 for nearly 800 cycles under limited electrolyte compared with 40 cycles of the electrodes without GOPS.Also,the optimized electrode exhibits excellent rate capability.The use of GOPS greatly improves the interface compatibility between Si and PEDOT:PSS.XPS Ar+etching depth analysis proved that the addition of GOPS is conducive to forming a more stable SEI.A full battery assembled with NCM 523 cathode delivers a high energy density of 520 Wh kg^−1,offering good stability.  相似文献   

6.
Recent developments in the synthesis of graphene-based structures focus on continuous improvement of porous nanostructures,doping of thin films,and mechanisms for the construction of threedimensional architectures.Herein,we synthesize creeper-like Ni3Si2/NiOOH/graphene nanostructures via low-pressure all-solid meltingreconstruction chemical vapor deposition.In a carbon-rich atmosphere,high-energy atoms bombard the Ni and Si surface,and reduce the free energy in the thermodynamic equilibrium of solid Ni–Si particles,considerably catalyzing the growth of Ni–Si nanocrystals.By controlling the carbon source content,a Ni3Si2 single crystal with high crystallinity and good homogeneity is stably synthesized.Electrochemical measurements indicate that the nanostructures exhibit an ultrahigh specific capacity of 835.3 C g^−1(1193.28 F g^−1)at 1 A g^−1;when integrated as an all-solidstate supercapacitor,it provides a remarkable energy density as high as 25.9 Wh kg^−1 at 750 W kg^−1,which can be attributed to the freestanding Ni3Si2/graphene skeleton providing a large specific area and NiOOH inhibits insulation on the electrode surface in an alkaline solution,thereby accelerating the electron exchange rate.The growth of the high-performance composite nanostructure is simple and controllable,enabling the large-scale production and application of microenergy storage devices.  相似文献   

7.
Conversion-type anode materials with a high charge storage capability generally su er from large volume expansion, poor electron conductivity, and sluggish metal ion transport kinetics. The electrode material described in this paper, namely cobalt sulphide nanoparticles encapsulated in carbon cages(Co9S8@NC), can circumvent these problems. This electrode material exhibited a reversible sodium-ion storage capacity of 705 mAh g^-1 at 100 mA g^-1 with an extraordinary rate capability and good cycling stability. Mechanistic study using the in situ transmission electron microscope technique revealed that the volumetric expansion of the Co9S8 nanoparticles is bu ered by the carbon cages, enabling a stable electrode–electrolyte interface. In addition, the carbon shell with high-content doped nitrogen significantly enhances the electron conductivity of the Co9S8@NC electrode material and provides doping-induced active sites to accommodate sodium ions. By integrating the Co9S8@NC as negative electrode with a cellulose-derived porous hard carbon/graphene oxide composite as positive electrode and 1 M NaPF6 in diglyme as the electrolyte, the sodium-ion capacitor full cell can achieve energy densities of 101.4 and 45.8 Wh kg^-1 at power densities of 200 and 10,000 W kg^-1, respectively.  相似文献   

8.
Recently,multivalent metal-ion batteries have attracted considerable interests on the merits of their natural abundance and multielectron redox property.However,the development of Ca-ion battery is still in their preliminary stage because of the lack of suitable electrode material.The Ca-storage performance of the existing materials is still unsatisfactory with low capacity,poor cyclic stability,as well as sloping discharge profiles,which cannot provide stable energy output.In this work,transition metal oxide Sn-doped In2O3(ITO)has been explored as the aqueous Ca-ion battery anode,which could deliver a high discharge capacity of 71.2 mAh·g-1 with an ultra-flat discharge voltage plateau.The Ca storage mechanism was revealed to be reversible conversion reaction based on ex-situ X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),and transmission electron microscopy(TEM)characterizations.A flexible aqueous Ca-ion battery was subsequently assembled with zinc hexacyanoferrate(ZnHCF)cathode and ITO anode sandwiched by hydrogel electrolyte,which could deliver a high specific capacity of 75.3 mAh·g-1 at 0.4 A·g-1 with a flat output voltage plateau at around 0.8 V.The bendable and flexible Ca-ion battery with decent voltage output will pave the way for the energy storage devices towards practical applications in flexible and wearable electronics.  相似文献   

9.
In this work,a novel vacuum-assisted strategy is proposed to homogenously form Metal-organic frameworks within hollow mesoporous carbon nanospheres(HMCSs)via a solid-state reaction.The method is applied to synthesize an ultrafine CoSe2 nanocrystal@N-doped carbon matrix confined within HMCSs(denoted as CoSe2@NC/HMCS)for use as advanced anodes in highperformance potassium-ion batteries(KIBs).The approach involves a solvent-free thermal treatment to form a Co-based zeolitic imidazolate framework(ZIF-67)within the HMCS templates under vacuum conditions and the subsequent selenization.Thermal treatment under vacuum facilitates the infiltration of the cobalt precursor and organic linker into the HMCS and simultaneously transforms them into stable ZIF-67 particles without any solvents.During the subsequent selenization process,the“dual confinement system”,composed of both the N-doped carbon matrix derived from the organic linker and the small-sized pores of HMCS,can effectively suppress the overgrowth of CoSe2 nanocrystals.Thus,the resulting uniquely structured composite exhibits a stable cycling performance(442 mAh g^−1 at 0.1 A g^−1 after 120 cycles)and excellent rate capability(263 mAh g^−1 at 2.0 A g^−1)as the anode material for KIBs.  相似文献   

10.
Nitrogen-doped carbon materials with a large specific surface area,high conductivity,and adjustable microstructures have many prospects for energy-related applications.This is especially true for N-doped nanocarbons used in the electrocatalytic oxygen reduction reaction(ORR)and supercapacitors.Here,we report a low-cost,environmentally friendly,large-scale mechanochemical method of preparing N-doped porous carbons(NPCs)with hierarchical micro-mesopores and a large surface area via ball-milling polymerization followed by pyrolysis.The optimized NPC prepared at 1000°C(NPC-1000)offers excellent ORR activity with an onset potential(Eonset)and half-wave potential(E1/2)of 0.9 and 0.82 V,respectively(vs.a reversible hydrogen electrode),which are only approximately 30 mV lower than that of Pt/C.The rechargeable Zn–air battery assembled using NPC-1000 and the NiFe-layered double hydroxide as bifunctional ORR and oxygen evolution reaction electrodes offered superior cycling stability and comparable discharge performance to RuO2 and Pt/C.Moreover,the supercapacitor electrode equipped with NPC prepared at 800℃ exhibited a high specific capacity(431 F g^−1 at 10 mV s^−1),outstanding rate,performance,and excellent cycling stability in an aqueous 6-M KOH solution.This work demonstrates the potential of the mechanochemical preparation method of porous carbons,which are important for energy conversion and storage.  相似文献   

11.
Eighteen carotenoids as well as vitamin A and two forms of vitamin E (gamma- and alpha-tocopherol) have been separated from extracts of human plasma by high-performance liquid chromatography (HPLC) on reversed-phase and sillca-based nitrile-bonded columns. In the order of chromatographic elution on a C18 reversed-phase column, the carotenoids were identified as (3R,3'R,6'R)-beta, epsilon-carotene-3,3'-diol [(3R,3'R,6'R)-lutein], (3R,3'R)-beta, beta-carotene-3,3'-diol [(3R,3'R)-zeaxanthin], 5,6-dihydroxy-5,6-dihydro-psi,psi-carotene, 3-hydroxy-2',3'-didehydro-beta,epsilon-caroten-3-ol, 3-hydroxy-beta-carotene,psi,psi-carotene, 7,8-dihydro-psi,psi-carotene, beta,psi-carotene, 7,8,7',8'-tetrahydro-psi,psi-carotene, beta,epsilon-carotene, beta,beta-carotene, 7,8,11,12,7',8'-hexahydro-psi,psi-carotene, and 7,8,11,12,7',8'-11',12'-octahydro-psi,psi-carotene. The polar carotenoids, which eluted in the vicinity of lutein and were unresolved on the C18 column, have been separated on a nitrile-bonded column employing isocratic HPLC conditions. In the order of elution, the carotenoids were epsilon,epsilon-carotene-3,3'-dione, 3'-hydroxy-epsilon,epsilon-caroten-3-one, 5,6-dihydroxy-5,6-dihydro-psi,psi-carotene, 3-hydroxy-beta,epsilon-caroten-3'-one, (all-E,3R,3'R,6'R)-lutein, (all-E,3R,3'R)-zeaxanthin, and (all-E,3R,3'S,6'R)-beta,epsilon-carotene-3,3'-diol (3'-epilutein) followed by several geometrical isomers of lutein and zeaxanthin.  相似文献   

12.
Long-term leaching of Ca, Fe, Mg, K, Na, S, Al, As, Ba, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Zn, Mo, Sb, Si, Sn, Sr, Ti, V, P, Cl, and dissolved organic carbon from two different municipal solid waste incineration (MSWI) air-pollution-control residues was monitored during 24 months of column percolation experiments; liquid-to-solid (L/S) ratios of 200-250L/kg corresponding to more than 10,000 years in a conventional landfill were reached. Less than 2% of the initially present As, Cu, Pb, Zn, Cr, and Sb had leached during the course of the experiments. Concentrations of Cd, Fe, Mg, Hg, Mn, Ni, Co, Sn, Ti, and P were generally bellow 1microg/L; overall less than 1% of their mass leached. Column leaching data were further used in a two-step geochemical modeling in PHREEQC in order to (i) identify solubility controlling minerals and (ii) evaluate their interactions in a water-percolated column system over L/S of 250L/kg. Adequate predictions of pH, alkalinity, and the leaching of Ca, S, Al, Si, Ba, and Zn were obtained in a simultaneous calculation. Also, it was suggested that removal of Ca and S together with depletion of several minerals apparently caused dissolution of ettringite-like phases. In turn, significant increase in leaching of oxyanions (especially Sb and Cr) was observed at late stage of leaching experiments.  相似文献   

13.
Urban soil samples were analyzed for Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Pb, Sr and Zn by atomic absorption spectrophotometric method. Multivariate statistical approach was used to study the apportionment of selected metals in the soil samples during summer and winter. The degree of contamination along with the geoaccumulation index, enrichment factor and contamination factor was also evaluated. In water-extract of the soil samples, relatively higher levels were noted for Na, Ca, K, Fe, Mg, and Pb with average concentrations of 56.38, 33.82, 12.53, 7.127, 5.994, and 1.045 mg/kg during summer, while the mean metal levels during winter were 76.45, 38.05, 3.928, 0.627, 8.726, and 0.878 mg/kg, respectively. In case of acid-extract of the soils, Ca, Fe, Mg, Na, K, Mn and Sr were found at 27,531, 12,784, 2769, 999.9, 737.9, 393.5, and 115.1 mg/kg, during summer and 23,386, 3958, 3206, 254.6, 1511, 453.6, and 53.30 mg/kg, during winter, respectively. Most of the metals showed random distribution with diverse correlations in both seasons. Principal component analysis and cluster analysis revealed significant anthropogenic intrusions of Cd, Pb, Co, Cr, Cu, Li, Zn and Na in the soils. Geoaccumulation indices and contamination factors indicated moderate to heavy contamination for Pb and Cd in the soils, while enrichment factor exhibited significant enrichment (EF > 5) of Cd, Pb, Ca, Co, Li, Mn and Zn by anthropogenic activities. Overall, on the average basis, considerable degree of contamination (Cdeg > 16) was observed in both seasons, although it was higher in winter. Present metal levels were also compared with those reported from other areas around the world.  相似文献   

14.
This study describes the partitioning of 20 trace elements (As, B, Ba, Cd, Co, Cr, Cu, Hg, Li, Mn, Mo, Ni, P, Pb, Sb, Se, Sn, Tl, V, Zn) and eight major and minor elements (Al, Ca, Fe, K, Mg, Na, Si, Ti) during the combustion of high ash content lignite. The experiments were carried out in the 0.3 MW(t) Middle East Technical University (METU) atmospheric bubbling fluidized bed combustor (ABFBC) test rig with and without limestone addition. Inert bed material utilized in the experiments was bed ash obtained previously from the combustion of the same lignite without limestone addition in the same test rig. Concentrations of trace elements in coal, limestone, bottom ash, cyclone ash and filter ash were determined by inductively coupled plasma optical emission spectroscopy (ICP-OES). Partitioning of major and minor elements are influenced by the ash split between the bottom ash and fly ash and that the major proportion of most of the trace elements (As, Ba, Cr, Hg, Li, Mo, Ni, Sn, V, Zn) are recovered in fly ash. Limestone addition shifts the partitioning of Ba, Cr, Mo, Ni, Sn, V, Zn from bottom ash to fly ash.  相似文献   

15.
The elemental composition of three different Iranian cement samples was determined by instrumental neutron activation analysis with the aim of quality control. The mass fractions for 4 major (Ca, Si, Fe, Al) and the 21 minor and trace elements (Mg, V, Mn, Na, As, La, Sb, Sm, U, Ba, Ce, Co, Cr, Eu, Hf, Sc, Sr, Th, Zn, S, K) were determined. X-ray fluorescence analysis was also used. The results obtained by both methods for Na, Mg, Fe, Ca, and Al are in good agreement. On the whole, the Iranian cement quality is quite acceptable according to national and international standards.  相似文献   

16.
The plasma of cancer patients (n=112) and controls (n=118) were analysed for selected trace metals (Al, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Sb, Sr and Zn) by flame atomic absorption spectroscopy. In the plasma of cancer patients, mean concentrations of macronutrients/essential metals, Na, K, Ca, Mg, Fe and Zn were 3971, 178, 44.1, 7.59, 4.38 and 3.90 ppm, respectively, while the mean metal levels in the plasma of controls were 3844, 151, 74.2, 18.0, 6.60 and 2.50 ppm, respectively. Average concentrations of Cd, Cr, Cu, Mn, Mo, Ni, Pb, Sb, Sr and Zn were noted to be significantly higher in the plasma of cancer patients compared with controls. Very strong mutual correlations (r>0.70) in the plasma of cancer patients were observed between Fe-Mn, Ca-Mn, Ca-Ni, Ca-Co, Cd-Pb, Co-Ni, Mn-Ni, Mn-Zn, Cr-Li, Ca-Zn and Fe-Ni, whereas, Ca-Mn, Ca-Mg, Fe-Zn, Ca-Zn, Mg-Mn, Mg-Zn, Cd-Sb, Cd-Co, Cd-Zn, Co-Sb and Sb-Zn exhibited strong relationships (r>0.50) in the plasma of controls, all were significant at p<0.01. Principal component analysis (PCA) of the data extracted five PCs, both for cancer patients and controls, but with considerably different loadings. The average metals levels in male and female donors of the two groups were also evaluated and in addition, the general role of trace metals in the carcinogenesis was discussed. The study indicated appreciably different pattern of metal distribution and mutual relationships in the plasma of cancer patients in comparison with controls.  相似文献   

17.
This study describes the partitioning of 18 trace elements (As, Ba, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, P, Pb, Sb, Se, Sn, Tl, V, Zn) and 9 major and minor elements (Al, Ca, Fe, K, Mg, Na, S, Si, Ti) during co-firing of olive residue, hazelnut shell and cotton residue with high sulfur and ash content lignite in 0.3 MW(t) Middle East Technical University (METU) Atmospheric Bubbling Fluidized Bed Combustor (ABFBC) test rig with limestone addition. Concentrations of trace elements in coal, biomass, limestone, bottom ash, cyclone ash and filter ash were determined by inductively coupled plasma optical emission and mass spectroscopy (ICP-OES and ICP-MS). Partitioning of major and minor elements are influenced by the ash split between the bottom ash and fly ash and that the major proportion of most of the trace elements (As, Ba, Co, Cr, Cu, Li, Mn, Mo, Ni, Pb, Tl, V and Zn) are recovered in fly ash when firing lignite only. Co-firing lignite with biomass enhances partitioning of these elements to fly ash. Co-firing also shifts the partitioning of Cd, P, Sb and Sn from bottom to fly ash.  相似文献   

18.
系统介绍了发泡金属的力学性能、能量吸收性、耐火阻焰性、导热性、导电性、电磁屏蔽性、渗透性等性质。综述了它们在能量吸收器、消音器、过滤器、阻焰器、加热及热交换器、结构材料、催化剂及催化剂载体、多孔电极、电磁屏蔽材料、二次电池的极板材料以及由其制成的复合材料等方面的用途,展示了发泡金属的应用前景  相似文献   

19.
The patent information currently available for the former USSR, EAPO, Russian Federation, Turkmenistan, Belarus, Tajikistan, Kazakhstan, Azerbaijan, Moldova, Armenia, Ukraine, Georgia, Kyrgyzstan, the Baltic countries and Uzbekistan is described. It is a complicated scene, in terms of the extent and depth of coverage, the media employed (paper, CD, on-line), and the use of open access, charged INTERNET access and commercial databases.  相似文献   

20.
Green synthesis of metal nanoparticles (NPs) has now received the attention of researchers due to ease of preparation and its potential to overcome hazards of these chemicals for an eco‐friendly milieu. In this study, copper oxide (CuO) NPs were synthesised via Desmodium gangeticum aqueous root extract and standard chemical method, further characterised by UV–visible spectroscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, Thermogravimetric analysis and scanning electron microscopy. The nephrotoxicity of the NP obtained from two routes were compared and evaluated at subcellular level in Wistar rat, renal proximal epithelial cells (LLC PK1 cell lines) and isolated renal mitochondria. CuO NP synthesised by chemical route showed prominent nephrotoxicity measured via adverse cytotoxicity to LLC PK1 cells, elevated renal oxidative stress and damage to renal tissue (determined by impaired alanine transaminase, aspartate transaminase, urea, uric acid and creatinine in the blood). However, at the level of cell organelle, CuO NP from both routes are non‐toxic to mitochondrial functional activity. The authors’ finding suggests that CuO NP synthesised by chemical route may induce nephrotoxicity, but may be overcome by co‐administration of antioxidants, as it is not mito‐toxic.Inspec keywords: cellular biophysics, scanning electron microscopy, toxicology, nanomedicine, oxidation, nanoparticles, enzymes, blood, visible spectra, X‐ray diffraction, biochemistry, nanofabrication, antibacterial activity, ultraviolet spectra, copper compounds, Fourier transform infrared spectra, molecular biophysics, thermal analysis, biological tissuesOther keywords: green synthesised copper oxide nanoparticles, murine model, metal nanoparticles, chemicals, eco‐friendly milieu, copper oxide NPs, standard chemical method, X‐ray diffraction, scanning electron microscopy, subcellular level, renal proximal epithelial cells, LLC PK1 cell lines, renal mitochondria, renal tissue, cell organelle, mitochondrial functional activity, UV‐visible spectroscopy, Fourier transform infrared spectroscopy, nephrotoxicity, renal oxidative stress, Desmodium gangeticum aqueous root extract, thermogravimetric analysis, Wistar rat, cytotoxicity, impaired alanine transaminase, aspartate transaminase, urea, uric acid, creatinine, blood, CuO  相似文献   

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