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1.
Small ; 20(27): e2310915, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38267813

RESUMO

Lithium dendrites are easily generated for excessively-solved lithium ions (Li+) inside the lithium metal batteries, which will lead serious safety issues. In this experiment, carbon spheres (CS) are successfully anchored on TiO2 (CS@TiO2) in the hydrothermal polymerization, which is filtrated on the commercial PE separator (CS@TiO2@PE). The negative charge in CS can suppress random diffusion of anions through electrostatic interactions. Density functional theory (DFT) calculations show that CS contributes to the desolvation of Li+, thereby increasing the migration rate of Li+. Furthermore, TiO2 exhibits high affinity to liquid electrolytes and acts as a physical barrier to lithium dendrite formation. CS@TiO2 is a combination of the advantages of CS and TiO2. As results, the Li+ transference number of the CS@TiO2@PE separator can be promoted to 0.63. The Li||Li cell with the CS@TiO2@PE separator exhibits a stable cycle performance for more than 600 h and lower polarization voltage (17 mV) at 1 mA cm-2. The coulombic efficiency (CE) of the Li||Cu cells employe the CS@TiO2@PE separator is 81.63% over 130 cycles. The discharge capacity of LiFePO4||Li cells based on the CS@TiO2@PE separator is 1.73 mAh (capacity retention = 91.53% after 260 cycles). Thus, the CS@TiO2 layer inhibits lithium dendrite formation.

2.
Molecules ; 29(17)2024 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-39274938

RESUMO

The adsorption properties of microporous carbon materials modified with iron citrate were investigated. The carbon materials were produced based on resorcinol-formaldehyde resin, treated in a microwave assisted solvothermal reactor, and next carbonized in the tube furnace at a temperature of 700 °C under argon atmosphere. Iron citrate was applied as a modifier, added to the material precursor before the synthesis in the reactor, in the quantity enabling to obtain the nanocomposites with C:Fe mass ratio equal to 10:1. Some samples were additionally activated using potassium oxalate or potassium hydroxide. The phase composition of the produced nanocomposites was determined using the X-ray diffraction method. Scanning and transmission electron microscopy was applied to characterize the changes in samples' morphology resulting from the activation process and/or the introduction of iron into the carbon matrix. The adsorption of nitrogen from gas phase and dyes (methylene blue and congo red) from water solution on the obtained materials was investigated. In the case of methylene blue, the adsorption equilibrium isotherms followed the Langmuir isotherm model. However, in the case of congo red, a linear dependency of adsorption and concentration in a broad equilibrium concentration range was found and well-described using the Henry equation. The most efficient adsorption of methylene blue was noticed for the sample activated with potassium hydroxide and modified with iron citrate, and a maximum adsorption capacity of 696 mg/g was achieved. The highest congo red adsorption was noticed for the non-activated sample modified with iron citrate, and the partition coefficient for this material equaled 171 dm3/g.

3.
Angew Chem Int Ed Engl ; : e202411066, 2024 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-39092491

RESUMO

Energy storage in supercapacitors and hybrid zinc ion capacitors (ZIC) using porous carbon materials offers a promsing alternative method for clean energy solutions. The unique combination of hierarchical porous structure and nitrogen doping in these materials has demonstrated significant capacity for energy storage. Nevertheless, the full potential of these materials, particularly the relationship between pore structure configuration and performance, remains underexplored. Herein, a confined pyrolysis strategy based on the polymerization characteristics of polydopamine (PDA) was developed to construction of hollow carbon spheres with microporous/mesoporous dual shell structure. The depth of micropores and cavity can be controlled by adjusting the duration of heat treatment and hydrothermal treatment, in accordance with the decomposition and polymerization characteristics of PDA. Due to the elasticity of this structure, the relationship between the micro/mesoporous depth of the prepared carbon spheres and the energy storage performance in supercapacitors and ZIC is established. Through optimizing the ion transport capacity of carbon spheres and considering the influence of its internal cavity structure on energy storage, the resulting carbon spheres exhibit high specific capacitance of 389 F g-1 in supercapacitor and specific capacitance of 260 F g-1 and excellent stability with 99.3% retention after 30000 chare/discharge cycles in ZIC.

4.
Small ; 19(12): e2207197, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36587968

RESUMO

Hollow carbon spheres are potential candidates for lightweight microwave absorbers. However, the skin effect of pure carbon-based materials frequently induces a terrible impedance mismatching issue. Herein, small-sized NiO/Ni particles with heterojunctions on the N-doped hollow carbon spheres (NHCS@NiO/Ni) are constructed using SiO2 as a sacrificing template. The fabricated NHCS@NiO/Ni displayed excellent microwave absorbability with a minimum reflection loss of -44.04 dB with the matching thickness of 2 mm and a wider efficient absorption bandwidth of 4.38 GHz with the thickness of 1.7 mm, superior to most previously reported hollow absorbers. Experimental results demonstrated that the excellent microwave absorption property of the NHCS@NiO/Ni are attributed to balanced dielectric loss and optimized impedance matching characteristic due to the presence of NiO/Ni heterojunctions. Theoretical calculations suggested that the redistribution of charge at the interfaces and formation of dipoles induced by N dopants and defects are responsible for the enhanced conduction and polarization losses of NHCS@NiO/Ni. The simulations for the surface current and power loss densities reveal that the NHCS@NiO/Ni has- applicable attenuation ability toward microwave under the practical application scenario. This work paves an efficient way for the reasonable design of small-sized particles with well-defined heterojunctions on hollow nanostructures for high-efficiency microwave absorption.

5.
Small ; 19(27): e2208228, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36974577

RESUMO

The rational structural design of the electrode materials is significant to enhance the electrochemical performance for potassium ion storage, benefiting from the shortened ion diffusion distance, increased conductivity, and pseudo-capacitance promotion. Herein, hydrated vanadium oxide (HVO) nanosheets with enriched oxygen defects are well confined into hollow mesoporous carbon spheres (HMCS), producing Od -VOH@C nanospheres through one-step hydrothermal reaction. Attributed to the restricted growth in the HMCS, the HVO nanosheets are loosely packed, generating abundant interfacial boundaries and large specific areas. As a result, Od -VOH@C nanospheres show increased reaction kinetics and well buffer the volume effects for the K+ storage. Od -VOH@C delivers stable capacities of 138 mAh g-1 at 2.0 A g-1 over 10 000 cycles in half-cells attributed to the high pseudo-capacitance contribution. The K+ storage mechanism of insertion and conversion reaction is confirmed by ex situ X-ray diffraction, Raman, and X-ray photoelectron spectroscopy analyses. Moreover, the symmetric potassium-ion capacitors of Od -VOH@C//Od -VOH@C deliver a high energy density of 139.6 Wh kg-1 at the power density of 948.3 W kg-1 .

6.
Small ; 19(43): e2302634, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37376867

RESUMO

Electrochemical bioassays based on oxidase reactions are frequently used in biological sciences and medical industries. However, the enzymatic reaction kinetics are severely restricted by the poor solubility and slow diffusion rate of oxygen in conventional solid-liquid diphase reaction systems, which inevitably compromises the detection accuracy, linearity, and reliability of the oxidase-based bioassay. Herein, an effective solid-liquid-air triphase bioassay system is provided that uses hydrophobic hollow carbon spheres (HCSs) as oxygen nanocarriers. The oxygen stored in the cavity of HCS can rapidly diffuse to the oxidase active sites through the mesoporous carbon shell, providing sufficient oxygen for oxidase-based enzymatic reactions. As a result, the triphase system can significantly improve the enzymatic reaction kinetics and obtain a 20-fold higher linear detection range than the normal diphase system. Other biomolecules can also be determined using this triphase technique, and the triphase design strategy offers a new route to address the gas deficiency problem in catalytic reactions that involve gas consumption.


Assuntos
Bioensaio , Carbono , Reprodutibilidade dos Testes , Oxigênio , Oxirredutases
7.
Small ; 19(30): e2300150, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37058083

RESUMO

Direct removal of carbon dioxide (CO2 ) from the atmosphere, known as direct air capture (DAC) is attracting worldwide attention as a negative emission technology to control atmospheric CO2 concentrations. However, the energy-intensive nature of CO2 absorption-desorption processes has restricted deployment of DAC operations. Catalytic solvent regeneration is an effective solution to tackle this issue by accelerating CO2 desorption at lower regeneration temperatures. This work reports a one-step synthesis methodology to prepare monodispersed carbon nanospheres (MCSs) using trisodium citrate as a structure-directing agent with acidic sites. The assembly of citrate groups on the surface of MCSs enables consistent spherical growth morphology, reduces agglomeration and enhances water dispersibility. The functionalization-assisted synthesis produces uniform, hydrophilic nanospheres of 100-600 nm range. This work also demonstrates that the prepared MCSs can be further functionalized with strong Brønsted acid sites, providing high proton donation ability. Furthermore, the materials can be effectively used in a wide range of amino acid solutions to substantially accelerate CO2 desorption (25.6% for potassium glycinate and 41.1% for potassium lysinate) in the DAC process. Considering the facile synthesis of acidic MCSs and their superior catalytic efficiency, these findings are expected to pave a new path for energy-efficient DAC.

8.
Small ; 19(28): e2301226, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36974608

RESUMO

The rational design of lightweight, broad-band, and high-performance microwave absorbers is urgently required for addressing electromagnetic pollution issue. Metal single atoms (M-SAs) absorbers receive considerable interest in the field of microwave absorption due to the unique electronic structures of M-SAs. However, the simultaneous engineering of the morphology and electronic structure of M-SAs based absorbers remains challenging. Herein, a template-assisted method is utilized to fabricate isolated Co-SAs on N-doped hollow carbon spheres (NHCS@Co-SAs) for high-performance microwave absorption. The combination of atomically dispersed Co sites and hollow supports endows NHCS@Co-SAs with excellent microwave absorption properties. Typically, at an ultralow filler content of 8 wt%, the minimum reflection loss and effective absorption bandwidth of the NHCS@Co-SAs are up to -44.96 dB and 5.25 GHz, respectively, while the absorbing thickness is only 2 mm. Theoretical calculations and experimental results indicate that the impedance matching characteristic and dielectric loss of the NHCSs can be tuned via the introduction of M-SAs, which are responsible for the excellent microwave absorption properties of NHCS@Co-SAs. This work provides an atomic-level insight into the relationship between the electronic states of absorbers and their microwave absorption properties for developing advanced microwave absorbers.

9.
Int J Mol Sci ; 24(4)2023 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-36835241

RESUMO

Recent innovative adsorption technologies for water purification rely on micrometer-sized activated carbon (AC) for ultrafast adsorption or in situ remediation. In this study, the bottom-up synthesis of tailored activated carbon spheres (aCS) from sucrose as renewable feedstock is demonstrated. The synthesis is based on a hydrothermal carbonization step followed by a targeted thermal activation of the raw material. This preserves its excellent colloid properties, i.e., narrow particle size distribution around 1 µm, ideal spherical shape and excellent aqueous dispersibility. We investigated the ageing of the freshly synthesized, highly de-functionalized AC surface in air and aqueous media under conditions relevant to the practice. A slow but significant ageing due to hydrolysis and oxidation reactions was observed for all carbon samples, leading to an increase of the oxygen contents with storage time. In this study, a tailored aCS product was generated within a single pyrolysis step with 3 vol.-% H2O in N2 in order to obtain the desired pore diameters and surface properties. Adsorption characteristics, including sorption isotherms and kinetics, were investigated with monochlorobenzene (MCB) and perfluorooctanoic acid (PFOA) as adsorbates. The product showed high sorption affinities up to log (KD/[L/kg]) of 7.3 ± 0.1 for MCB and 6.2 ± 0.1 for PFOA, respectively.


Assuntos
Carvão Vegetal , Poluentes Químicos da Água , Poluentes Químicos da Água/análise , Água , Coloides , Adsorção , Cinética
10.
Small ; 18(10): e2106513, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34927355

RESUMO

Porous and hollow carbon materials have great superiority and prospects in electrochemical energy applications, especially for surface charge storage due to the high active surface. Herein, a general strategy is developed to synthesize mesoporous hollow carbon spheres (MHCS) with controllable texture and compositions by the synergistic effect of dopamine polymerization and metal catalysis (Cu, Bi, Zn). Mesoporous MHCS-Cu and MHCS-Bi are regular spheres, while mesoporous MHCS-Zn possesses an inward concave texture, and simultaneously has a very high surface area of 1675.5 m2 g-1 and lower oxygen content through the catalytic deoxygenation effect. MHCS-Zn displays an exceptional sodium storage kinetics and excellent long cycling life with 171.9 mAh g-1 after 2500 cycles at 5 A g-1 in compatible ether-based electrolytes. Such electrolyte enables enhanced solvated Na+ transport kinetics with appropriate electrostatic interactions at the surface of carbon anode as revealed by molecular dynamics simulations and molecular surface electrostatic potential calculations. Such an anode also displays basically constant capacity working at 0 °C, and still delivers 140 mAh g-1 at 3 A g-1 under -20 °C. Moreover, MHCS-Zn anode is coupled with Na3 V2 (PO4 )3 cathode to construct a hybrid capacitor, which exhibits a high energy density of 145 Wh Kg-1 at a very high power of 8009 W kg-1 .

11.
Small ; 18(8): e2104469, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35015928

RESUMO

Lithium-sulfur batteries (LSBs) are attracting much attention due to their high theoretical energy density and are considered to be the predominant competitors for next-generation energy storage systems. The practical commercial application of LSBs is mainly hindered by the severe "shuttle effect" of the lithium polysulfides (LiPSs) and the serious damage of lithium dendrites. Various carbon materials with different characteristics have played an important role in overcoming the above-mentioned problems. Carbon spheres (CSs) are extensively explored to enhance the performance of LSBs owing to their superior structures. The review presents the state-of-the-art advances of CSs for advanced high-energy LSBs, including their preparation strategies and applications in inhibiting the "shuttle effect" of the LiPSs and protecting lithium anodes. The unique restriction effect of CSs on LiPSs is explained from three working mechanisms: physical confinement, chemical interaction, and catalytic conversion. From the perspective of interfacial engineering and 3D structure designing, the protective effect of CSs on the lithium anode is also analyzed. Not only does this review article contain a summary of CSs in LSBs, but also future directions and prospects are discussed. The systematic discussions and suggested directions can enlighten thoughts in the reasonable design of CSs for LSBs in near future.


Assuntos
Carbono , Lítio , Carbono/química , Fontes de Energia Elétrica , Eletrodos , Lítio/química , Enxofre
12.
Small ; 18(8): e2104296, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34873861

RESUMO

The investigation of carbonaceous-based anode materials will promote the fast application of low-cost potassium-ion batteries (PIBs). Here a nitrogen and oxygen co-doped yolk-shell carbon sphere (NO-YS-CS) is constructed as anode material for K-ion storage. The novel architecture, featuring with developed porous structure and high surface specific area, is beneficial to achieving excellent electrochemical kinetics behavior and great electrode stability from buffering the large volume expansion. Furthermore, the N/O heteroatoms co-doping can not only boost the adsorption and intercalation ability of K-ion but also increase the electron transfer capability. It is also demonstrated by experimental results and DFT calculations that K-ion insertion/extraction proceeds through both intercalation and surface capacitive adsorption mechanisms. As expected, the NO-YS-CS electrodes show high initial charge capacity of 473.7 mAh g-1 at 20 mA g-1 , ultralong cycling life over 2500 cycles with the retention of 85.8% at 500 mA g-1 , and superior rate performance (183.3 mAh g-1 at 1.0 A g-1 ). The K-ion full cell, with a high energy density of 271.4 Wh kg-1 and an excellent cyclic stability over 500 cycles, is successfully fabricated with K2 Fe[Fe(CN)6 ] cathode. This work will provide new insight on the synthesis and mechanism understanding of high-performance hard carbon anode for PIBs.

13.
Nanotechnology ; 33(27)2022 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-35344938

RESUMO

In this work, a kind of boron doped carbon spheres (B-CSs) was successfully synthesized utilizing maize starch as carbon source and boric acid as dopant via facile solvothermal method. The chemical structure of the prepared B-CSs was systemically investigated by TEM, FT-IR, XRD, XPS and EDS. The synthesized B-CSs feature spherical structure with average size of ∼254 nm and exhibit strong photoluminescence (PL) with maximum emission at a wavelength of ∼453 nm under irradiation at 350 nm, leading to a quantum yield of 6.2%. Furthermore, the aqueous pH and Cr(VI) has a significantly various impact on the PL intensity of B-CSs, which can be flexibly utilized as the PL sensor for detection aqueous pH and Cr(VI) in aqueous. Particularly, the B-CSs have a desirable sensitivity and selectivity for detection of Cr(VI) with a low detection limit of ∼0.34µmol l-1. Conclusively, our work provides a novel and dual-functional fluorescent sensor for detection of the pH and toxic metal ions in water environment.

14.
Mikrochim Acta ; 189(8): 271, 2022 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-35789294

RESUMO

A signal-on sandwich-like electrochemical immunosensor was built for determination of cytokeratin 19 fragments 21-1 (CYFRA 21-1) in non-small cell lung cancer (NSCLC) by confining electroactive dye (e.g., methylene blue, MB) as a probe for amplifying signals. Specifically, core-shell gold@rhodium dendritic nanocrystals (Au@Rh DNCs) behaved as a substrate for primary antibody and accelerate interfacial electron transfer. Besides, hollow carbon spheres (HCSs) were subsequently modified with polydopamine (PDA) and PtPd nanoparticles for sequential integration of the secondary antibody and confinement of MB as a label, termed as MB/PtPd/PDA/HCSs for clarity. The built sensors showed a broad linear range (100 fg mL-1 ~ 100 ng mL-1) for detection of CYFRA 21-1 with an ultra-low detection limit (31.72 fg mL-1, S/N = 3), coupled with satisfactory performance in human serum samples. This work can be explored for assays of other proteins and provides some constructive insights for early and accurate diagnosis of NSCLC.


Assuntos
Técnicas Biossensoriais , Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Nanopartículas , Anticorpos , Antígenos de Neoplasias , Carbono , Carcinoma Pulmonar de Células não Pequenas/diagnóstico , Humanos , Imunoensaio , Indóis , Queratina-19 , Neoplasias Pulmonares/diagnóstico , Polímeros
15.
Molecules ; 27(17)2022 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-36080147

RESUMO

The adsorption properties of microporous spherical carbon materials obtained from the resorcinol-formaldehyde resin, treated in a solvothermal reactor heated with microwaves and then subjected to carbonization, are presented. The potassium-based activation of carbon spheres was carried out in two ways: solution-based and solid-based methods. The effect of various factors, such as chemical agent selection, chemical activating agent content, and the temperature or time of activation, was investigated. The influence of microwave treatment on the adsorption properties was also investigated and described. The adsorption performance of carbon spheres was evaluated in detail by examining CO2 adsorption from the gas phase.

16.
Molecules ; 27(4)2022 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-35209176

RESUMO

Zinc chloride and potassium oxalate are often applied as activating agents for carbon materials. In this work, we present the preparation of ZnO/carbon spheres composites using resorcinol-formaldehyde resin as a carbon source in a solvothermal reactor heated with microwaves. Zinc chloride as a zinc oxide source and potassium oxalate as an activating agent were applied. The effect of their addition and preparation conditions on the adsorption properties towards carbon dioxide at 0 °C and 25 °C were investigated. Additionally, for all tested sorbents, the CO2 sorption tests at 40 °C, carried out utilizing a thermobalance, confirmed the trend of sorption capacity measured at 0 and 25 °C. Furthermore, the sample activated using potassium oxalate and modified using zinc chloride (a carbon-to-zinc ratio equal to 10:1) displayed not only a high CO2 adsorption capacity (2.69 mmol CO2/g at 40 °C) but also exhibited a stable performance during the consecutive multicycle adsorption-desorption process.

17.
Molecules ; 27(20)2022 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-36296393

RESUMO

This work aimed to obtain hybrid composites based on photoactive metal oxide and carbon having adsorption properties. The materials, composed of titanium dioxide or zinc oxide and spherical carbon, were obtained from resorcinol-formaldehyde resin, treated in a solvothermal reactor heated with microwaves and then subjected to carbonization, were received. The functional groups of pure carbon spheres (unsaturated stretching C=C, stretching C-OH and C-H bending vibrations), CS/ZnO and CS/TiO2 samples were determined by FT-IR analysis. The characteristic bands for ZnO and TiO2 were observed below 1000 cm-1. The thermal oxidative properties are similar for TiO2- and ZnO-modified carbon spheres. We have observed that the increased carbon sphere content in nanocomposites results in starting the decomposition process at a lower temperature, therefore, nanocomposites have a broader combustion temperature range. The effect of the oxides' addition to carbon spheres on their adsorption properties was evaluated in detail by examining CO2 adsorption from the gas phase. The selectivity of CO2 over N2 at a temperature of 25 °C and pressure of 1 bar (a novelty in testing CS-based sorbents) calculated for 3.00 CS/TiO2 and 4.00 CS/ZnO was 15.09 and 16.95, respectively. These nanocomposites exhibit excellent cyclic stability checked over 10 consecutive adsorption-desorption cycles.

18.
Angew Chem Int Ed Engl ; 61(45): e202212542, 2022 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-36093883

RESUMO

Trapping the active sites on the exterior surface of hollow supports can reduce mass transfer resistance and enhance atomic utilization. Herein, we report a facile chemical vapor deposition strategy to synthesize single-Ni atoms decorated hollow S/N-doped football-like carbon spheres (Ni SAs@S/N-FCS). Specifically, the CdS@3-aminophenol/formaldehyde is carbonized into S/N-FCS. The gas-migrated Ni species are anchored on the surface of S/N-FCS simultaneously, yielding Ni SAs@S/N-FCS. The obtained catalyst exhibits outstanding performance for alkaline oxygen evolution reaction (OER) with an overpotential of 249 mV at 10 mA cm-2 , a small Tafel slope of 56.5 mV dec-1 , and ultra-long stability up to 166 hours without obvious fading. Moreover, the potential-driven dynamic behaviors of Ni-N4 sites and the contribution of the S dopant at different locations in the matrix to the OER activity are revealed by the operando X-ray absorption spectroscopy and theoretical calculations, respectively.

19.
Chemistry ; 27(38): 9820-9829, 2021 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-33886138

RESUMO

In this work, we first synthesized polyacrylic acid (PAA) spheres and then used PAA as a template to load Co(OH)2 particles onto its surface. The product of CoS2 nanoparticles dispersed in N-doped hollow spheres (N-HCS) was prepared through sulfurization treatment (CoS2 /S@N-HCS). During the sulfuration process, sulfur penetrates into the PAA, embedding into the graphite layer along with the carbonization process. It was found that during the charging and discharging process, the sulfur in the carbon layer will gradually dissolve out, thereby forming new ion diffusion channels in the carbon spheres and exposing more CoS2 active sites. The CoS2 /S@N-HCS composite exhibits a specific capacity of 729.6 mAh g-1 after 500 cycles at a current density of 1 A g-1 . The sodium-storage mechanism and reaction kinetics of the materials were further measured by in-situ electrochemical impedance spectroscopy, ex-situ X-ray diffraction, capacitance performance evaluation, and galvanostatic intermittent titration technique. The excellent cycling performance and rate capability demonstrated that the CoS2 /S@N-HCS is a potential and prospective anode material for sodium-ion batteries.

20.
Nanotechnology ; 32(48)2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34416745

RESUMO

Fabricating sulfur host for the cathode with strong confinement effect and high dispersion of sulfur is vitally important to the development of high-performance lithium sulfur batteries. Benefiting from their unique and tunable structure, good conductivity and chemical inertness, hollow porous carbon materials has been considered as a promising candidate. Herein, precisely designed waxberry-like hierarchical hollow carbon spheres (h-CNS) have been synthesized as the sulfur micro-containers for lithium sulfur batteries. The prepared h-CNS/S electrode shows a good rate capability of 1311 mAh g-1at 0.1 C and 962 mAh g-1at 1 C. In addition, the h-CNS/S electrode also shows satisfactory long cycle performance with 622 mAh g-1at 0.5 C and 400 mAh g-1at 4 C over 600 cycles. The desirable performance can be attributed to the wedge-shape micro-containers which improve the high dispersion of sulfur inside the channels and inhibit the loss of intermediate polysulfide. Moreover, the unique structure can also enhance the transfer of both lithium ions and electrons which benefits to the rate capability of the lithium sulfur batteries.

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