Manganese-based chalcogenides have significant potential as anodes for sodium-ion batteries(SIBs) due to their high theoretical specific capacity, abundant natural reserves, and environmental friendliness. However, th...Manganese-based chalcogenides have significant potential as anodes for sodium-ion batteries(SIBs) due to their high theoretical specific capacity, abundant natural reserves, and environmental friendliness. However, their application is hindered by poor cycling stability, resulting from severe volume changes during cycling and slow reaction kinetics due to their complex crystal structure. Here, an efficient and straightforward strategy was employed to in-situ encapsulate single-phase porous nanocubic MnS_(0.5)Se_(0.5) into carbon nanofibers using electrospinning and the hard template method, thus forming a necklace-like porous MnS_(0.5)Se_(0.5)-carbon nanofiber composite(MnS_(0.5)Se_(0.5)@N-CNF). The introduction of Se significantly impacts both the composition and microstructure of MnS_(0.5)Se_(0.5), including lattice distortion that generates additional defects, optimization of chemical bonds, and a nano-spatially confined design. In situ/ex-situ characterization and density functional theory calculations verified that this MnS_(0.5)Se_(0.5)@N-CNF allevi- ates the volume expansion and facilitates the transfer of Na+/electron. As expected, MnS_(0.5)Se_(0.5)@N-CNF anode demonstrates excellent sodium storage performance, characterized by high initial Coulombic efficiency(90.8%), high-rate capability(370.5 m Ahg^(-1) at 10 Ag^(-1)) and long durability(over 5000 cycles at 5 Ag^(-1)). The MnS_(0.5)Se_(0.5)@N-CNF//NVP@C full cell, assembled with MnS_(0.5)Se_(0.5)@N-CNF as anode and Na_(3)V_(2)(PO_4)_(3)@C as cathode, exhibits a high energy density of 254 Wh kg^(-1) can be provided. This work presents a novel strategy to optimize the design of anode materials through structural engineering and Se substitution, while also elucidating the underlying reaction mechanisms.展开更多
High-entropy metal phosphide(HEMP)has considerable potential as an electrocatalyst owing to its beneficial properties,including high-entropy alloy synergy as well as the controllable structure and high conductivity of...High-entropy metal phosphide(HEMP)has considerable potential as an electrocatalyst owing to its beneficial properties,including high-entropy alloy synergy as well as the controllable structure and high conductivity of phosphides.Herein,electrospinning and in situ phosphating were employed to prepare three-dimensional(3D)networks of self-supporting HEMP nanofibers with varying degrees of phosphate content.Comprehensive characterizations via X-ray diffraction and X-ray photoelectron spectroscopy,as well as density functional theory calculations,demonstrate that the introduction of phosphorus(P)atoms to HEMP carbon nanofibers mediates their electronic structure,leads to lattice expansion,which in turn enhances their catalytic performance in the hydrogen evolution reaction(HER).Moreover,the formation of metal-P bonds weakens metal-metal interaction and decreases the free energy of hydrogen adsorption,contributing to the exceptional activity observed in the HEMP catalyst.Electrochemical measurements demonstrate that the HEMP-0.75 catalyst with an ultralow loading of 1.22 wt%ruthenium(Ru)exhibits the highest HER catalytic activity and stability in a 1 M KOH electrolyte,achieving a minimal overpotential of 26 mV at a current density of 10 mA·cm^(-2)and Tafel slope of 50.9 mV·dec^(-1).展开更多
Adsorption as an effective technique for the remediation of wastewater has been widely used in industrial wastewater treatment due to the advantage of cost-effectiveness,availability of the adsorbent and ease of opera...Adsorption as an effective technique for the remediation of wastewater has been widely used in industrial wastewater treatment due to the advantage of cost-effectiveness,availability of the adsorbent and ease of operation.However,the low adsorption capacity of the reported adsorbents is still a challenge for wastewater treatment with highefficiency.Here,we developed a super adsorbent(SUA-1),which was a kind of porous carbon nanofibers derived from a composite of PAN-based electrospinning and ZIF-8(PAN/ZIF-8)via simple heat treatment process.The asprepared SUA showed an ultra-high adsorption capacity for adsorbing methyl blue(MB)at nearly three times its own weight,as high as 2998.18 mg/g.A series tests demonstrated that the pore-making effect of ZIF-8 during heat treatment process endowed high BET surface area and generated ZnO components as chemical adsorption center.Under the synergistic effect of bonding and non-bonding forces including ionic bond,electrostatic interaction,andπ-πinteraction,the adsorption capacity has been greatly improved.In view of promising efficiency,this work provides guidance and insights for the preparation of highly efficient adsorbents based on electrospinning derived porous carbon nanofibers.展开更多
The need for bi-functional catalysts that facilit-ate both the oxygen reduction(ORR)and carbon dioxide re-duction(CO_(2)RR)reactions arises from their potential to help solve the critical problems of carbon neutrality...The need for bi-functional catalysts that facilit-ate both the oxygen reduction(ORR)and carbon dioxide re-duction(CO_(2)RR)reactions arises from their potential to help solve the critical problems of carbon neutrality and renew-able energy conversion.However,there are few reports on the development of bi-functional catalysts for zinc-air bat-tery-driven CO_(2)RR devices.We introduce a novel approach for synthesizing Fe_(2)N/Fe_(3)C species embedded in nitrogen-doped carbon nanofibers by electrospinning a solution of Hemin and polyacrylonitrile in N,N-dimethylformamide.The material has an exceptional catalytic performance,with a half-wave potential of 0.91 V versus RHE for the ORR and values of over 90%for both the selectivity and Faradaic efficiency for the CO_(2)RR.The high catalytic performances are attrib-uted to the strong coupling between the Fe_(3)C/Fe_(2)N heterostructure and the Fe-N-C sites in the nitrogen-doped carbon nan-ofibers.Notably,both Fe_(3)C and Fe_(2)N play distinct roles in both the ORR and CO_(2)RR.This investigation indicates a way for designing advanced carbon-based bi-functional catalysts for use in this field.展开更多
The extensive use of quinolones leads to serious residues in different water matrices and consequent ecological risks.Magnetic Co-Cu incorporated in-situ in carbon nanofibers(Co-Cu/CNFs)were prepared for peroxymonocar...The extensive use of quinolones leads to serious residues in different water matrices and consequent ecological risks.Magnetic Co-Cu incorporated in-situ in carbon nanofibers(Co-Cu/CNFs)were prepared for peroxymonocarbonate(PMC)activation during quinolone degradation.The as-synthesized nanocomposites exhibited a high aspect ratio,large specific surface area(283.6 m^(2)g^(-1)),encapsulated Co and Cu nanoparticles and magnetic response(6.2 emu g^(-1)).Complete pefloxacin degradation can be achieved in 8 min in the Co-Cu/CNFs activated PMC system,and six other commonly used and detected quinolones can also be completely removed in approximately half an hour.Furthermore,ciprofloxacin can be completely decomposed within 50 min in different actual water matrices.The remarkable catalytic activities of Co-Cu/CNFs might be attributed to the increasing conductivity and electron transfer capability according to electrochemical impedance spectroscopy.The Co-Cu/CNFs activated PMC system is superior to other counterpart activated peroxide systems in terms of faster removal rates,less leakage of metal ions and greater proportions of heterogeneous catalytic reactions.Singlet oxygen was the primary contributor to ciprofloxacin degradation,followed by hydroxyl,carbonate and superoxide anion radicals.The pharmacophores of 26ciprofloxacin transformation products were converted by reactive species,including 81%pharmacophore removal which is beneficial for subsequent natural attenuation or biological treatment.展开更多
Flexible energy storage devices have been paid much attention and adapts to apply in various fields.Benefiting from the active sites of boron(B)and phosphorus(P)doping materials,co-doped carbon materials are widely us...Flexible energy storage devices have been paid much attention and adapts to apply in various fields.Benefiting from the active sites of boron(B)and phosphorus(P)doping materials,co-doped carbon materials are widely used in energy storage devices for the enhanced electrochemical performance.Herein,B and P co-doped flexible carbon nanofibers with nitrogen-rich(B-P/NC)are investigated with electro-spinning for sodium-ion battery.The flexible of binderless B-P/NC with annealing of 600℃(B-P/NC-600)exhibits the remarkable performance for the robust capacity of 200 mAh/g at 0.1 A/g after 500 cycles and a durable reversible capacity of 160 m Ah/g even at 1 A/g after 12,000 cycles,exhibiting the equally commendable stability of flexible B-P/NC-600.In addition,B-P/NC-600 delivers the reversible capacity of265 m Ah/g with the test temperature of 60℃.More importantly,the flexible B-P/NC-600 is fabricated as anode for the whole battery,delivering the capacity of 90 m Ah/g at 1 A/g after 200 cycles.Meanwhile,theoretical calculation further verified that boron and phosphorus co-doping can improve the adsorption capacity of nitrogen carbon materials.The favorable performance of flexible B-P/NC-600 can be ascribed to the nitrogen-rich carbon nanofibers with three-dimensional network matrix for the more active site of boron and phosphorus co-doping.Our work paves the way for the improvement of flexible anodes and wide-operating temperature of sodium-ion batteries by doping approach of much heteroatom.展开更多
Among their several unique properties,the high electrical conductivity and mechanical strength of carbon nanofibers make them suitable for applications such as catalyst support for fuel cells,flexible electrode materi...Among their several unique properties,the high electrical conductivity and mechanical strength of carbon nanofibers make them suitable for applications such as catalyst support for fuel cells,flexible electrode materials for secondary batteries,and sensors.However,their performance requires improvement for practical applications.Several methods have been pursued to achieve this,such as growing carbon nanotubes from carbon nanofibers;however,the transition metal catalyst used to grow carbon nanotubes causes problems,including side reactions.This study attempts to address this issue by growing numerous branched carbon nanofibers from the main carbon nanofibers using alkali metals.Excellent electrical conductivity is achieved by growing densely branched carbon nanofibers.Consequently,a current collector,binder,and conductive material-free anode material is realized,exhibiting excellent electrochemical performance compared with existing carbon nanofibers.The proposed method is expected to be a powerful tool for secondary batteries and have broad applicability to various fields.展开更多
The efficient electrocatalytic nitrate(NO_(3)^(−))reduction to ammonia(NRA)offers a sustainable alternative for both environmental remediation and ammonia synthesis.Developing advanced electrocatalysts with rationally...The efficient electrocatalytic nitrate(NO_(3)^(−))reduction to ammonia(NRA)offers a sustainable alternative for both environmental remediation and ammonia synthesis.Developing advanced electrocatalysts with rationally designed spatial arrangement of active sites and optimizing the synergetic effect among components are crucial for high efficiency and selectivity.Herein,we present Fe/N active sites decorated on porous carbon nanofibers(CNFs)with encapsulated FeCo nanoparticles(FeCo@CNFs-Fe/N)as electrocatalysts for NRA.The FeCo@CNFs-Fe/N catalyst demonstrates exceptional performance,achieving a high ammonia yield of 498.18μmol/(h·g_(cat)).Meanwhile,the enhanced reduction activity,especially the reduction in overpotential by 0.565 V,is 3–10 times higher than that of FeCo-encapsulated and Fe/N-modified CNFs-based catalysts.The enhanced catalytic activity is attributed to the efficient structure design and optimized spatial distribution of active sites,which enhance the electron transfer rate and decrease the reaction energy barrier.Mechanistic studies reveal that the synergetic effect between encapsulated nanoparticles and surface-modified Fe/N sites plays a crucial role in promoting efficient nitrate adsorption and selective ammonia production.These findings highlight the potential of strategically engineered CNF-based composites for nitrate reduction and other advanced electrocatalytic applications.展开更多
High-performance and low-cost anode materials are critical for superior sodium-ion batteries(SIBs).Herein,high-yield porous carbon nanofiber(CNF)anode materials(named CNFs@Cu–Ni)are prepared by chemical vapor deposit...High-performance and low-cost anode materials are critical for superior sodium-ion batteries(SIBs).Herein,high-yield porous carbon nanofiber(CNF)anode materials(named CNFs@Cu–Ni)are prepared by chemical vapor deposition using a specialized nanoporous Cu–Ni alloy catalyst.Density functional theory calculations indicate that Ni incorporation results in a shift of the d-band center of the catalyst from−2.34157 to−1.93682 eV.This phenomenon elucidates the remarkable adsorption capacity of the Cu–Ni catalyst toward C2H2,thereby facilitating the catalytic growth of high-performance CNFs.With this approach,a superior yield of 258.6%for deposited carbon is reached after growth for 1 h.The CNFs@Cu–Ni anode presents an outstanding discharge capacity of 193.6 mAh·g^(−1) at 1.0 A·g^(−1)over 1000 cycles and an exceptional rate capability by maintaining a capacity of 158.9 mAh·g^(−1)even at 5.0 A·g^(−1)in an ether-based electrolyte.It also exhibits excellent performance in the CNFs@Cu–Ni//NVP full battery attributed to the presence of abundant Na+adsorption sites on its surface.This study presents a new concept for the advancement of high-performance carbonaceous electrodes for SIBs.展开更多
Aqueous zinc-ion batteries(AZIBs)have emerged as promising,practical energy storage devices based on their non-toxic nature,environmental friendliness,and high energy density.However,excellent rate characteristics and...Aqueous zinc-ion batteries(AZIBs)have emerged as promising,practical energy storage devices based on their non-toxic nature,environmental friendliness,and high energy density.However,excellent rate characteristics and stable long-term cycling performance are essential.These essential aspects create a need for superior cathode materials,which represents a substantial challenge.In this study,we used MXenes as a framework for NH_(4)V_(4)O_(10)(NVO)construction and developed electrodes that combined the high capacity of NVO with the excellent conductivity of MXene/carbon nanofibers(MCNFs).We explored the electrochemical characteristics of electrodes with varying NVO contents.Considering the distinctive layered structure of NVO,the outstanding conductivity of MCNFs,and the strong synergies between the two components.NVO-MCNFs exhibited better charge transfer compared with earlier materials,as well as more ion storage sites,excellent conductivity,and short ion diffusion pathways.A composite electrode with optimized NVO content exhibited an excellent specific capacitance of 360.6mAh g^(-1) at 0.5 A g^(-1) and an outstanding rate performance.In particular,even at a high current density of 10 A g^(-1),the 32NVO-MCNF exhibited impressive cycling stability:88.6%over 2500 cycles.The mechanism involved was discovered via comprehensive characterization.We expect that the fabricated nanofibers will be useful in energy storage and conversion systems.展开更多
The dual system capable of solar-driven interfacial steam production and all-weather hydropower generation is emerging as a potential way to alleviate freshwater shortage and energy crisis.However,the intrinsic mechan...The dual system capable of solar-driven interfacial steam production and all-weather hydropower generation is emerging as a potential way to alleviate freshwater shortage and energy crisis.However,the intrinsic mechanism of hydroelectricity generation powered by the interaction between seawater and material structure is vague,and it remains challenging to develop dual-functional evaporators with high photothermal conversion efficiency and ionic selectivity.Herein,an all-weather dual-function evaporator based on porous carbon fiber-like(PCF)is acquired through the pyrolysis of barium-based metal-organic framework(Ba-BTEC),which is originated from waste polyimide.The PCF-based evaporator/device exhibits a high steam generation rate of 2.93 kg m^(-2)h^(-1)in seawater under 1 kW m^(-2)irradiation,along with the notable opencircuit voltage of 0.32 V,owing to the good light absorption ability,optimal wettability,and suitable aperture size.Moreover,molecular dynamics simulation result reveals that Na+tends to migrate rapidly within the nanoporous channels of PCF,owing to a strong affinity between oxygen-containing functional group and water molecules.This work not only proposes an eco-friendly strategy for constructing low-cost fulltime freshwater-hydroelectric co-generation device,but also contributes to the understanding of evaporation-driven energy harvesting technology.展开更多
Sodium-ion batteries(SIBs)show promising potential in the field of electrochemical energy storage due to their cost-effectiveness and similar operational mechanisms to lithium-ion batteries(LIBs).However,the dramatic ...Sodium-ion batteries(SIBs)show promising potential in the field of electrochemical energy storage due to their cost-effectiveness and similar operational mechanisms to lithium-ion batteries(LIBs).However,the dramatic volume expansion of electrode materials and the slow reaction kinetics caused by the large sodium ion(Na^(+))radius hinder the practical application of SIBs,Here,we successfully prepared SnS_(2-x)Se_(x)nanodots embedded within N-doped carbon nanofibers(CNF)for use as electrode materials of SIBs,The introduction Se provided abundant anionic defect sites for Na+storage and enlarged the interlayer spacing of SnS_(2).In addition,the ultraifne nanodot structure reduces the volume expansion of SnS_(2-x)Se_(x)and shortens the ion transport path.As an anode of SIBs,SnS_(2-x)Se_(x)/CNF demonstrates remarkable reversible capacity(719 mAh g^(-1)at 0.5 A g^(-1)),along with rapid charging ability(completing a charge in just 127 s).Meanwhile,the assembled full-cell battery manifested exceptional energy density of 165.8 Wh kg^(-1)at a high-power output of 5526 W kg^(-1).This study presents an effective strategy for fabricating highperformance sulphide-based anode materials for SIBs,offering broad prospects for application.展开更多
Carbon-based electromagnetic wave(EMW)absorbing materials attached with metal sulfides famous for good dielectric properties are favored by researchers,which can form heterogeneous interfaces and thus provide suppleme...Carbon-based electromagnetic wave(EMW)absorbing materials attached with metal sulfides famous for good dielectric properties are favored by researchers,which can form heterogeneous interfaces and thus provide supplementary loss mechanisms to make up for the deficiencies of a single material in energy attenuation.Here,Co_(9)S_(8)/Co@coral-like carbon nanofibers(CNFs)/porous carbon hybrids are successfully fabricated by hydrothermal and chemical vapor deposition.The samples have exceptional EMW absorb-ing properties,with a minimum reflection loss of-57.48 dB at a thickness of 2.94 mm and an effective absorption bandwidth of up to 6.10 GHz at only 2.20 mm.The interlocking structure formed by Co@coral-like CNFs,interfacial polarization generated by heterostructure of Co_(9)S_(8),abundant defects and large specific surface area resulted from porous properties are important factors in attaining magnetic-dielectric balance and excellent absorption performance.Different matrixes are selected instead of paraffin to investigate the effect of matrix materials on EMW absorbing capacity.Besides,the EMW attenuation potential for practical applications is also demonstrated by radar cross-section simulations,electric field intensity distribution and power loss density.This work provides a novel strategy for designing outstanding EMW absorbers with unique microstructures using facile and low-cost synthetic routes.展开更多
The Cu^(+)/Cu^(0)sites of copper-based catalysts are crucial for enhancing the production of multicarbon(C_(2+))products from electrochemical CO_(2)reduction reaction(eCO_(2)RR).However,the unstable Cu^(+)and insuffic...The Cu^(+)/Cu^(0)sites of copper-based catalysts are crucial for enhancing the production of multicarbon(C_(2+))products from electrochemical CO_(2)reduction reaction(eCO_(2)RR).However,the unstable Cu^(+)and insufficient Cu^(+)/Cu^(0)active sites lead to their limited selectivity and stability for C_(2+)production.Herein,we embedded copper oxide(CuO_(x))particles into porous nitrogen-doped carbon nanofibers(CuO_(x)@PCNF)by pyrolysis of the electrospun fiber film containing ZIF-8 and Cu_(2)O particles.The porous nitrogendoped carbon nanofibers protected and dispersed Cu^(+)species,and its micro porous structure enhanced the interaction between CuO_(x)and reactants during eCO_(2)RR.The obtained CuO_(x)@PCNF created more effective and stable Cu^(+)/Cu^(0)active sites.It showed a high Faradaic efficiency of 62.5%for C_(2+)products in Hcell,which was 2 times higher than that of bare CuO_(x)(~31.1%).Furthermore,it achieved a maximum Faradaic efficiency of 80.7%for C_(2+)products in flow cell.In situ characterization and density functional theory(DFT)calculation confirmed that the N-doped carbon layer protected Cu^(+)from electrochemical reduction and lowered the energy barrier for the dimerization of^(*)CO.Stable and exposed Cu^(+)/Cu^(0)active sites enhanced the enrichment of^(*)CO and promoted the C-C coupling reaction on the catalyst surface,which facilitated the formation of C_(2+)products.展开更多
Unidirectional carbon/carbon（C/C） composites modified with in situ grown carbon nanofibers（CNFs） were prepared by catalysis chemical vapor deposition. The effect of in situ grown CNFs on the flexural properties of...Unidirectional carbon/carbon（C/C） composites modified with in situ grown carbon nanofibers（CNFs） were prepared by catalysis chemical vapor deposition. The effect of in situ grown CNFs on the flexural properties of the C/C composites was investigated by detailed analyses of destructive process. The results show that there is a sharp increase in the flexural load-displacement curve in the axial direction of the CNF-C/C composites, followed by a serrated yielding phenomenon similar to the plastic materials. The failure mode of the C/C composites modified with in situ grown CNFs is changed from the pull-out of single fiber to the breaking of fiber bundles. The existence of interfacial layer composed by middle-textured pyrocarbon, CNFs and high-textured pyrocarbon can block the crack propagation and change the propagation direction of the main crack, which leads to the higher flexural strength and modulus of C/C composites.展开更多
Changes of a 65Ni25Cu10A1203 catalyst consisting of Ni-enriched and Cu-enriched alloys were investigated in the bulk and on the surface during the growth of nitrogen-doped carbon nanofibers （N-CNFs） by decomposition...Changes of a 65Ni25Cu10A1203 catalyst consisting of Ni-enriched and Cu-enriched alloys were investigated in the bulk and on the surface during the growth of nitrogen-doped carbon nanofibers （N-CNFs） by decomposition of a 50%C2I-I4/50%NH3 mixture using in situ X-ray diffraction （XRD） analysis, ex situ X-ray photoelectron spectroscopy （XPS） and transmission electron microscopy （TEM） techniques. It was shown that N-CNF growth at 450-650 ℃is accompanied by dissolution of carbon and nitrogen in the Ni-enriched alloy, whereas Cu-enriched alloy remains inactive. A correlation between nickel and copper surface concentrations and properties of N-CNFs in relation to the nitrogen content was found. It was demonstrated that phase composition of the catalyst during N-CNF growth determines the type of N-CNFs structure.展开更多
Dramatic capacity fading and poor rate performance are two main obstacles that severely hamper the widespread application of the Si anode owing to its large volume variation during cycling and low intrinsic electrical...Dramatic capacity fading and poor rate performance are two main obstacles that severely hamper the widespread application of the Si anode owing to its large volume variation during cycling and low intrinsic electrical conductivity.To mitigate these issues,free-standing N-doped porous carbon nanofibers sheathed pumpkin-like Si/C composites(Si/C-ZIF-8/CNFs)are designed and synthesized by electrospinning and carbonization methods,which present greatly enhanced electrochemical properties for lithium-ion battery anodes.This particular structure alleviates the volume variation,promotes the formation of stable solid electrolyte interphase(SEI)film,and improves the electrical conductivity.As a result,the as-obtained free-standing Si/C-ZIF-8/CNFs electrode delivers a high reversible capacity of 945.5 mAh g^(-1) at 0.2 A g^(-1) with a capacity retention of 64% for 150 cycles,and exhibits a reversible capacity of 538.6 mA h g^(-1) at 0.5 A g^(-1) over 500 cycles.Moreover,the full cell composed of a freestanding Si/C-ZIF-8/CNFs anode and commercial LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)(NCM)cathode shows a capacity of 63.4 mA h g^(-1) after 100 cycles at 0.2 C,which corresponds to a capacity retention of 60%.This rational design could provide a new path for the development of high-performance Si-based anodes.展开更多
Li metal anodes(LMAs)has attracted extensive research interest because of its extremely high theoretical capacity(3860 m Ah/g)at low redox potential(-3.04 V vs.standard hydrogen electrode).However,the extremely high c...Li metal anodes(LMAs)has attracted extensive research interest because of its extremely high theoretical capacity(3860 m Ah/g)at low redox potential(-3.04 V vs.standard hydrogen electrode).However,the extremely high chemical reactivity and the intrinsic“hostless”nature of LMAs bring about serious dendritic growth and dramatic volume change during the plating/strapping process,thus resulting in poor Coulombic efficiency,short lifespan,and severe safety concerns.Of various strategies,the construction of three-dimensional carbonaceous scaffolds for LMAs can substantially reduce the local current density,inhibit Li dendrite growth,and accommodate volume variation.Electrospinning is a simple yet effective strategy to fabricate carbon nanofibers(CNFs),which have been regarded as promising skeletons for LMAs,owing to their large surface areas,good electrical conductivity,and high porosity.In this Mini Review,we briefly introduce the fabrication of CNFs using electrospinning and the modification of CNFs.We highlight the recent advances in electrospun CNF skeletons for LMAs,including pure CNF and CNF-based composite scaffolds.Finally,we discuss the remaining challenges of electrospun CNF scaffolds for LMAs and provide possible solutions to push forward the advancement in this field.展开更多
In this work, a CoNxC active sites-rich three-dimensional porous carbon nanofibers network derived from bacterial cellulose and bimetal-ZIFs is prepared via a nucleation growth strategy and a pyrolysis process.The mat...In this work, a CoNxC active sites-rich three-dimensional porous carbon nanofibers network derived from bacterial cellulose and bimetal-ZIFs is prepared via a nucleation growth strategy and a pyrolysis process.The material displays excellent electrocatalytic activity for the oxygen reduction reaction, reaching a high limiting diffusion current density of -7.8 mA cm^(-2), outperforming metal–organic frameworks derived multifunctional electrocatalysts, and oxygen evolution reaction and hydrogen evolution reaction with low overpotentials of 380 and 107 mV, respectively. When the electrochemical properties are further evaluated, the electrocatalyst as an air cathode for Zn-air batteries exhibits a high cycling stability for63 h as well as a maximum power density of 308 mW cm^(-2), which is better than those for most Zn-air batteries reported to date. In addition, a power density of 152 mW cm^(-2) is provided by the solid-state Zn-air batteries, and the cycling stability is outstanding for 24 h. The remarkable electrocatalytic properties are attributed to the synergistic effect of the 3 D porous carbon nanofibers network and abundant inserted CoNxC active sites, which enable the fast transmission of ions and mass and simultaneously provide a large contact area for the electrode/electrolyte.展开更多
Onedimensional porous carbons bearing high surface areas and sufficient heteroatom doped functionalities are essential for advanced electrochemical energy storage devices,especially for developing freestanding film el...Onedimensional porous carbons bearing high surface areas and sufficient heteroatom doped functionalities are essential for advanced electrochemical energy storage devices,especially for developing freestanding film electrodes.Here we develop a porous,nitrogenenriched,freestanding hollow carbon nanofiber(PNFHCF)electrode material via filtration of polypyrrole(PPy)hollow nanofibers formed by in situ selfdegraded templateassisted strategy,followed by NH3assisted carbonization.The PNFHCF retains the freestanding film morphology that is composed of threedimensional networks from the entanglement of 1D nanofiber and delivers 3.7fold increase in specific surface area(592 m^(2)g^(-1))compared to the carbon without NH_(3)treatment(FHCF).In spite of the enhanced specific surface area,PNFHCF still exhibits comparable high content of surface N functionalities(8.8%,atom fraction)to FHCF.Such developed hierarchical porous structure without sacrificing N doping functionalities together enables the achievement of high capacity,highrate property and good cycling stability when applied as selfsupporting anode in lithiumion batteries,superior to those of FHCF without NH3 treatment.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 22225902, U22A20436, 22209185)National Key Research&Development Program of China (2022YFE0115900, 2023YFA1507101, 2021YFA1501500)+1 种基金the Self-deployment Project Research Program of Haixi Institutes,Chinese Academy of Sciences (No. CXZX-2022-GH04, CXZX-2023-JQ08)Science and Technology Program of Fuzhou (2023-P-009)。
文摘Manganese-based chalcogenides have significant potential as anodes for sodium-ion batteries(SIBs) due to their high theoretical specific capacity, abundant natural reserves, and environmental friendliness. However, their application is hindered by poor cycling stability, resulting from severe volume changes during cycling and slow reaction kinetics due to their complex crystal structure. Here, an efficient and straightforward strategy was employed to in-situ encapsulate single-phase porous nanocubic MnS_(0.5)Se_(0.5) into carbon nanofibers using electrospinning and the hard template method, thus forming a necklace-like porous MnS_(0.5)Se_(0.5)-carbon nanofiber composite(MnS_(0.5)Se_(0.5)@N-CNF). The introduction of Se significantly impacts both the composition and microstructure of MnS_(0.5)Se_(0.5), including lattice distortion that generates additional defects, optimization of chemical bonds, and a nano-spatially confined design. In situ/ex-situ characterization and density functional theory calculations verified that this MnS_(0.5)Se_(0.5)@N-CNF allevi- ates the volume expansion and facilitates the transfer of Na+/electron. As expected, MnS_(0.5)Se_(0.5)@N-CNF anode demonstrates excellent sodium storage performance, characterized by high initial Coulombic efficiency(90.8%), high-rate capability(370.5 m Ahg^(-1) at 10 Ag^(-1)) and long durability(over 5000 cycles at 5 Ag^(-1)). The MnS_(0.5)Se_(0.5)@N-CNF//NVP@C full cell, assembled with MnS_(0.5)Se_(0.5)@N-CNF as anode and Na_(3)V_(2)(PO_4)_(3)@C as cathode, exhibits a high energy density of 254 Wh kg^(-1) can be provided. This work presents a novel strategy to optimize the design of anode materials through structural engineering and Se substitution, while also elucidating the underlying reaction mechanisms.
基金supported by the National Natural Science Foundation of China(Nos.22103045 and 52273077)the State Key Laboratory of Bio-Fibers and Eco-Textiles,Qingdao University(Nos.ZDKT202108,RZ2000003334 and G2RC202022)support from the Australian National Fabrication Facility’s Queensland Node(No.ANFF-Q),the UQ-Yonsei International Research Project,and the JST-ERATO Yamauchi Materials Space-Tectonics Project(No.JPMJER2003).
文摘High-entropy metal phosphide(HEMP)has considerable potential as an electrocatalyst owing to its beneficial properties,including high-entropy alloy synergy as well as the controllable structure and high conductivity of phosphides.Herein,electrospinning and in situ phosphating were employed to prepare three-dimensional(3D)networks of self-supporting HEMP nanofibers with varying degrees of phosphate content.Comprehensive characterizations via X-ray diffraction and X-ray photoelectron spectroscopy,as well as density functional theory calculations,demonstrate that the introduction of phosphorus(P)atoms to HEMP carbon nanofibers mediates their electronic structure,leads to lattice expansion,which in turn enhances their catalytic performance in the hydrogen evolution reaction(HER).Moreover,the formation of metal-P bonds weakens metal-metal interaction and decreases the free energy of hydrogen adsorption,contributing to the exceptional activity observed in the HEMP catalyst.Electrochemical measurements demonstrate that the HEMP-0.75 catalyst with an ultralow loading of 1.22 wt%ruthenium(Ru)exhibits the highest HER catalytic activity and stability in a 1 M KOH electrolyte,achieving a minimal overpotential of 26 mV at a current density of 10 mA·cm^(-2)and Tafel slope of 50.9 mV·dec^(-1).
基金Natural Science Foundation of China(22134005,22204011)Chongqing Talents Program for Outstanding Scientists(cstc2021ycjh-bgzxm0179)。
文摘Adsorption as an effective technique for the remediation of wastewater has been widely used in industrial wastewater treatment due to the advantage of cost-effectiveness,availability of the adsorbent and ease of operation.However,the low adsorption capacity of the reported adsorbents is still a challenge for wastewater treatment with highefficiency.Here,we developed a super adsorbent(SUA-1),which was a kind of porous carbon nanofibers derived from a composite of PAN-based electrospinning and ZIF-8(PAN/ZIF-8)via simple heat treatment process.The asprepared SUA showed an ultra-high adsorption capacity for adsorbing methyl blue(MB)at nearly three times its own weight,as high as 2998.18 mg/g.A series tests demonstrated that the pore-making effect of ZIF-8 during heat treatment process endowed high BET surface area and generated ZnO components as chemical adsorption center.Under the synergistic effect of bonding and non-bonding forces including ionic bond,electrostatic interaction,andπ-πinteraction,the adsorption capacity has been greatly improved.In view of promising efficiency,this work provides guidance and insights for the preparation of highly efficient adsorbents based on electrospinning derived porous carbon nanofibers.
文摘The need for bi-functional catalysts that facilit-ate both the oxygen reduction(ORR)and carbon dioxide re-duction(CO_(2)RR)reactions arises from their potential to help solve the critical problems of carbon neutrality and renew-able energy conversion.However,there are few reports on the development of bi-functional catalysts for zinc-air bat-tery-driven CO_(2)RR devices.We introduce a novel approach for synthesizing Fe_(2)N/Fe_(3)C species embedded in nitrogen-doped carbon nanofibers by electrospinning a solution of Hemin and polyacrylonitrile in N,N-dimethylformamide.The material has an exceptional catalytic performance,with a half-wave potential of 0.91 V versus RHE for the ORR and values of over 90%for both the selectivity and Faradaic efficiency for the CO_(2)RR.The high catalytic performances are attrib-uted to the strong coupling between the Fe_(3)C/Fe_(2)N heterostructure and the Fe-N-C sites in the nitrogen-doped carbon nan-ofibers.Notably,both Fe_(3)C and Fe_(2)N play distinct roles in both the ORR and CO_(2)RR.This investigation indicates a way for designing advanced carbon-based bi-functional catalysts for use in this field.
基金financially supported by the National Key R&D Program of China(Nos.2023YFC3708903,2021YFC3200101)the International Science&Technology Innovation Program of Chinese Academy of Agriculture Science(Nos.CAAS-CFSGLCA-IEDA-202302,CAAS-ZDRW202110)the People?s Republic of China and Republic of Korea Young Scientist Exchange Program
文摘The extensive use of quinolones leads to serious residues in different water matrices and consequent ecological risks.Magnetic Co-Cu incorporated in-situ in carbon nanofibers(Co-Cu/CNFs)were prepared for peroxymonocarbonate(PMC)activation during quinolone degradation.The as-synthesized nanocomposites exhibited a high aspect ratio,large specific surface area(283.6 m^(2)g^(-1)),encapsulated Co and Cu nanoparticles and magnetic response(6.2 emu g^(-1)).Complete pefloxacin degradation can be achieved in 8 min in the Co-Cu/CNFs activated PMC system,and six other commonly used and detected quinolones can also be completely removed in approximately half an hour.Furthermore,ciprofloxacin can be completely decomposed within 50 min in different actual water matrices.The remarkable catalytic activities of Co-Cu/CNFs might be attributed to the increasing conductivity and electron transfer capability according to electrochemical impedance spectroscopy.The Co-Cu/CNFs activated PMC system is superior to other counterpart activated peroxide systems in terms of faster removal rates,less leakage of metal ions and greater proportions of heterogeneous catalytic reactions.Singlet oxygen was the primary contributor to ciprofloxacin degradation,followed by hydroxyl,carbonate and superoxide anion radicals.The pharmacophores of 26ciprofloxacin transformation products were converted by reactive species,including 81%pharmacophore removal which is beneficial for subsequent natural attenuation or biological treatment.
基金supported by Natural Science Foundation of China(No.6230031623)the Natural Science Foundation of Hunan Province(No.2024JJ5127)+2 种基金the Education Department of Hunan Province(No.22B0580)the Scientific Research and Innovation Foundation of Hunan University of Technology(No.CX2317)the Innovation and Entrepreneurship Training Project for College Students(No.S202311535061)。
文摘Flexible energy storage devices have been paid much attention and adapts to apply in various fields.Benefiting from the active sites of boron(B)and phosphorus(P)doping materials,co-doped carbon materials are widely used in energy storage devices for the enhanced electrochemical performance.Herein,B and P co-doped flexible carbon nanofibers with nitrogen-rich(B-P/NC)are investigated with electro-spinning for sodium-ion battery.The flexible of binderless B-P/NC with annealing of 600℃(B-P/NC-600)exhibits the remarkable performance for the robust capacity of 200 mAh/g at 0.1 A/g after 500 cycles and a durable reversible capacity of 160 m Ah/g even at 1 A/g after 12,000 cycles,exhibiting the equally commendable stability of flexible B-P/NC-600.In addition,B-P/NC-600 delivers the reversible capacity of265 m Ah/g with the test temperature of 60℃.More importantly,the flexible B-P/NC-600 is fabricated as anode for the whole battery,delivering the capacity of 90 m Ah/g at 1 A/g after 200 cycles.Meanwhile,theoretical calculation further verified that boron and phosphorus co-doping can improve the adsorption capacity of nitrogen carbon materials.The favorable performance of flexible B-P/NC-600 can be ascribed to the nitrogen-rich carbon nanofibers with three-dimensional network matrix for the more active site of boron and phosphorus co-doping.Our work paves the way for the improvement of flexible anodes and wide-operating temperature of sodium-ion batteries by doping approach of much heteroatom.
基金supported by the Ministry of Education of the Republic of Korea and the National Research Foundation of Korea(NRF2023R1A2C2004191)supported by Korea Basic Science Institute(National research Facilities and Equipment Center)grant funded by Ministry of Education(grant No.2022R1A6C101B738).
文摘Among their several unique properties,the high electrical conductivity and mechanical strength of carbon nanofibers make them suitable for applications such as catalyst support for fuel cells,flexible electrode materials for secondary batteries,and sensors.However,their performance requires improvement for practical applications.Several methods have been pursued to achieve this,such as growing carbon nanotubes from carbon nanofibers;however,the transition metal catalyst used to grow carbon nanotubes causes problems,including side reactions.This study attempts to address this issue by growing numerous branched carbon nanofibers from the main carbon nanofibers using alkali metals.Excellent electrical conductivity is achieved by growing densely branched carbon nanofibers.Consequently,a current collector,binder,and conductive material-free anode material is realized,exhibiting excellent electrochemical performance compared with existing carbon nanofibers.The proposed method is expected to be a powerful tool for secondary batteries and have broad applicability to various fields.
基金supported by Shanghai Science and Technology Plan Project(No.23ZR1467000)the Fundamental Research Funds for the Central University(No.22120240354)+1 种基金the National Natural Science Foundation of China(No.22131004)the Leading Scientific Research Project from China National Nuclear Corporation(No.CNNC–CXLM-202205).
文摘The efficient electrocatalytic nitrate(NO_(3)^(−))reduction to ammonia(NRA)offers a sustainable alternative for both environmental remediation and ammonia synthesis.Developing advanced electrocatalysts with rationally designed spatial arrangement of active sites and optimizing the synergetic effect among components are crucial for high efficiency and selectivity.Herein,we present Fe/N active sites decorated on porous carbon nanofibers(CNFs)with encapsulated FeCo nanoparticles(FeCo@CNFs-Fe/N)as electrocatalysts for NRA.The FeCo@CNFs-Fe/N catalyst demonstrates exceptional performance,achieving a high ammonia yield of 498.18μmol/(h·g_(cat)).Meanwhile,the enhanced reduction activity,especially the reduction in overpotential by 0.565 V,is 3–10 times higher than that of FeCo-encapsulated and Fe/N-modified CNFs-based catalysts.The enhanced catalytic activity is attributed to the efficient structure design and optimized spatial distribution of active sites,which enhance the electron transfer rate and decrease the reaction energy barrier.Mechanistic studies reveal that the synergetic effect between encapsulated nanoparticles and surface-modified Fe/N sites plays a crucial role in promoting efficient nitrate adsorption and selective ammonia production.These findings highlight the potential of strategically engineered CNF-based composites for nitrate reduction and other advanced electrocatalytic applications.
基金financially supported by the National Natural Science Foundation of China(Nos.52271011 and 52102291)the Structure Design and Mass Preparation of High Stability and Low Cost PEM Hydroelectrolysis Non-Iridium Catalyst,China(No.KC22453)
文摘High-performance and low-cost anode materials are critical for superior sodium-ion batteries(SIBs).Herein,high-yield porous carbon nanofiber(CNF)anode materials(named CNFs@Cu–Ni)are prepared by chemical vapor deposition using a specialized nanoporous Cu–Ni alloy catalyst.Density functional theory calculations indicate that Ni incorporation results in a shift of the d-band center of the catalyst from−2.34157 to−1.93682 eV.This phenomenon elucidates the remarkable adsorption capacity of the Cu–Ni catalyst toward C2H2,thereby facilitating the catalytic growth of high-performance CNFs.With this approach,a superior yield of 258.6%for deposited carbon is reached after growth for 1 h.The CNFs@Cu–Ni anode presents an outstanding discharge capacity of 193.6 mAh·g^(−1) at 1.0 A·g^(−1)over 1000 cycles and an exceptional rate capability by maintaining a capacity of 158.9 mAh·g^(−1)even at 5.0 A·g^(−1)in an ether-based electrolyte.It also exhibits excellent performance in the CNFs@Cu–Ni//NVP full battery attributed to the presence of abundant Na+adsorption sites on its surface.This study presents a new concept for the advancement of high-performance carbonaceous electrodes for SIBs.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean Government(MSIT)(Nos.RS-2023-00217581 and RS-2023-00304768)the National Research Council of Science&Technology(NST)grant by the Korean Government(MSIT)(No.CAP 22073-000).
文摘Aqueous zinc-ion batteries(AZIBs)have emerged as promising,practical energy storage devices based on their non-toxic nature,environmental friendliness,and high energy density.However,excellent rate characteristics and stable long-term cycling performance are essential.These essential aspects create a need for superior cathode materials,which represents a substantial challenge.In this study,we used MXenes as a framework for NH_(4)V_(4)O_(10)(NVO)construction and developed electrodes that combined the high capacity of NVO with the excellent conductivity of MXene/carbon nanofibers(MCNFs).We explored the electrochemical characteristics of electrodes with varying NVO contents.Considering the distinctive layered structure of NVO,the outstanding conductivity of MCNFs,and the strong synergies between the two components.NVO-MCNFs exhibited better charge transfer compared with earlier materials,as well as more ion storage sites,excellent conductivity,and short ion diffusion pathways.A composite electrode with optimized NVO content exhibited an excellent specific capacitance of 360.6mAh g^(-1) at 0.5 A g^(-1) and an outstanding rate performance.In particular,even at a high current density of 10 A g^(-1),the 32NVO-MCNF exhibited impressive cycling stability:88.6%over 2500 cycles.The mechanism involved was discovered via comprehensive characterization.We expect that the fabricated nanofibers will be useful in energy storage and conversion systems.
基金supported by National Natural Science Foundation of China(No.52373099)the Innovation and Talent Recruitment Base of New Energy Chemistry and Device(No.B21003)。
文摘The dual system capable of solar-driven interfacial steam production and all-weather hydropower generation is emerging as a potential way to alleviate freshwater shortage and energy crisis.However,the intrinsic mechanism of hydroelectricity generation powered by the interaction between seawater and material structure is vague,and it remains challenging to develop dual-functional evaporators with high photothermal conversion efficiency and ionic selectivity.Herein,an all-weather dual-function evaporator based on porous carbon fiber-like(PCF)is acquired through the pyrolysis of barium-based metal-organic framework(Ba-BTEC),which is originated from waste polyimide.The PCF-based evaporator/device exhibits a high steam generation rate of 2.93 kg m^(-2)h^(-1)in seawater under 1 kW m^(-2)irradiation,along with the notable opencircuit voltage of 0.32 V,owing to the good light absorption ability,optimal wettability,and suitable aperture size.Moreover,molecular dynamics simulation result reveals that Na+tends to migrate rapidly within the nanoporous channels of PCF,owing to a strong affinity between oxygen-containing functional group and water molecules.This work not only proposes an eco-friendly strategy for constructing low-cost fulltime freshwater-hydroelectric co-generation device,but also contributes to the understanding of evaporation-driven energy harvesting technology.
基金financially supported by the National Natural Science Foundation of China(22278348)Natural Science Foundation of Xinjiang Autonomous Region(2022D01D05)+1 种基金National guidance for local projects of Xinjiang Autonomous Region(ZYYD2025JD09)Tianshan Leading technology talents Program of Xinjiang Autonomous Region。
文摘Sodium-ion batteries(SIBs)show promising potential in the field of electrochemical energy storage due to their cost-effectiveness and similar operational mechanisms to lithium-ion batteries(LIBs).However,the dramatic volume expansion of electrode materials and the slow reaction kinetics caused by the large sodium ion(Na^(+))radius hinder the practical application of SIBs,Here,we successfully prepared SnS_(2-x)Se_(x)nanodots embedded within N-doped carbon nanofibers(CNF)for use as electrode materials of SIBs,The introduction Se provided abundant anionic defect sites for Na+storage and enlarged the interlayer spacing of SnS_(2).In addition,the ultraifne nanodot structure reduces the volume expansion of SnS_(2-x)Se_(x)and shortens the ion transport path.As an anode of SIBs,SnS_(2-x)Se_(x)/CNF demonstrates remarkable reversible capacity(719 mAh g^(-1)at 0.5 A g^(-1)),along with rapid charging ability(completing a charge in just 127 s).Meanwhile,the assembled full-cell battery manifested exceptional energy density of 165.8 Wh kg^(-1)at a high-power output of 5526 W kg^(-1).This study presents an effective strategy for fabricating highperformance sulphide-based anode materials for SIBs,offering broad prospects for application.
基金financially supported by the Natural Science Foundation of Shandong Province(Nos.ZR2021ME194,2022TSGC2448,and 2023TSGC0545)the Key Technology Research and Development Program of Shandong Province(No.2021ZLGX01).
文摘Carbon-based electromagnetic wave(EMW)absorbing materials attached with metal sulfides famous for good dielectric properties are favored by researchers,which can form heterogeneous interfaces and thus provide supplementary loss mechanisms to make up for the deficiencies of a single material in energy attenuation.Here,Co_(9)S_(8)/Co@coral-like carbon nanofibers(CNFs)/porous carbon hybrids are successfully fabricated by hydrothermal and chemical vapor deposition.The samples have exceptional EMW absorb-ing properties,with a minimum reflection loss of-57.48 dB at a thickness of 2.94 mm and an effective absorption bandwidth of up to 6.10 GHz at only 2.20 mm.The interlocking structure formed by Co@coral-like CNFs,interfacial polarization generated by heterostructure of Co_(9)S_(8),abundant defects and large specific surface area resulted from porous properties are important factors in attaining magnetic-dielectric balance and excellent absorption performance.Different matrixes are selected instead of paraffin to investigate the effect of matrix materials on EMW absorbing capacity.Besides,the EMW attenuation potential for practical applications is also demonstrated by radar cross-section simulations,electric field intensity distribution and power loss density.This work provides a novel strategy for designing outstanding EMW absorbers with unique microstructures using facile and low-cost synthetic routes.
基金supported by the National Natural Science Foundation of China(22222601 and 22076019)the Fundamental Research Funds for the Central Universities(DUT23LAB611).
文摘The Cu^(+)/Cu^(0)sites of copper-based catalysts are crucial for enhancing the production of multicarbon(C_(2+))products from electrochemical CO_(2)reduction reaction(eCO_(2)RR).However,the unstable Cu^(+)and insufficient Cu^(+)/Cu^(0)active sites lead to their limited selectivity and stability for C_(2+)production.Herein,we embedded copper oxide(CuO_(x))particles into porous nitrogen-doped carbon nanofibers(CuO_(x)@PCNF)by pyrolysis of the electrospun fiber film containing ZIF-8 and Cu_(2)O particles.The porous nitrogendoped carbon nanofibers protected and dispersed Cu^(+)species,and its micro porous structure enhanced the interaction between CuO_(x)and reactants during eCO_(2)RR.The obtained CuO_(x)@PCNF created more effective and stable Cu^(+)/Cu^(0)active sites.It showed a high Faradaic efficiency of 62.5%for C_(2+)products in Hcell,which was 2 times higher than that of bare CuO_(x)(~31.1%).Furthermore,it achieved a maximum Faradaic efficiency of 80.7%for C_(2+)products in flow cell.In situ characterization and density functional theory(DFT)calculation confirmed that the N-doped carbon layer protected Cu^(+)from electrochemical reduction and lowered the energy barrier for the dimerization of^(*)CO.Stable and exposed Cu^(+)/Cu^(0)active sites enhanced the enrichment of^(*)CO and promoted the C-C coupling reaction on the catalyst surface,which facilitated the formation of C_(2+)products.
基金Project(2011CB605804)supported by the National Basic Research Program of ChinaProject(51165006)supported by the National Natural Science Foundation of China+1 种基金Project(BY2013015-32)supported by Cooperative Innovation Fund-Prospective Project of Jiangsu Province,ChinaProject(JUSRP1045)supported by the Fundamental Research Funds for the Central Universities,China
文摘Unidirectional carbon/carbon（C/C） composites modified with in situ grown carbon nanofibers（CNFs） were prepared by catalysis chemical vapor deposition. The effect of in situ grown CNFs on the flexural properties of the C/C composites was investigated by detailed analyses of destructive process. The results show that there is a sharp increase in the flexural load-displacement curve in the axial direction of the CNF-C/C composites, followed by a serrated yielding phenomenon similar to the plastic materials. The failure mode of the C/C composites modified with in situ grown CNFs is changed from the pull-out of single fiber to the breaking of fiber bundles. The existence of interfacial layer composed by middle-textured pyrocarbon, CNFs and high-textured pyrocarbon can block the crack propagation and change the propagation direction of the main crack, which leads to the higher flexural strength and modulus of C/C composites.
基金supported by the Federal Target Program "Scientific and Educational Personnel of Innovative Russia" 2009–2013 (Agreement 8429)RFBR Grant No 12-03-01091-a+2 种基金Presidium RAS (Project 2451)Presidium SB RAS (Project 36)Integration Research Projects SB RAS No 75
文摘Changes of a 65Ni25Cu10A1203 catalyst consisting of Ni-enriched and Cu-enriched alloys were investigated in the bulk and on the surface during the growth of nitrogen-doped carbon nanofibers （N-CNFs） by decomposition of a 50%C2I-I4/50%NH3 mixture using in situ X-ray diffraction （XRD） analysis, ex situ X-ray photoelectron spectroscopy （XPS） and transmission electron microscopy （TEM） techniques. It was shown that N-CNF growth at 450-650 ℃is accompanied by dissolution of carbon and nitrogen in the Ni-enriched alloy, whereas Cu-enriched alloy remains inactive. A correlation between nickel and copper surface concentrations and properties of N-CNFs in relation to the nitrogen content was found. It was demonstrated that phase composition of the catalyst during N-CNF growth determines the type of N-CNFs structure.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.21965034,21703185,U1903217,51901013,and 21666037)the Xinjiang Autonomous Region Major Projects(2017A02004)+4 种基金the Leading Project Foundation of Science Department of Fujian Province(Grant No.2018H0034)the Resource Sharing Platform Construction Project of Xinjiang Province(PT1909)the Nature Science Foundation of Xinjiang Province(2017D01C074)the Opening Project of National Joint Engineering Research Center for Abrasion Control and Molding of Metal Materials,Henan University of Science and Technology(No.HKDNM201906)the Young Scholar Science Foundation of Xinjiang Educational Institutions(XJEDU2016S030)。
文摘Dramatic capacity fading and poor rate performance are two main obstacles that severely hamper the widespread application of the Si anode owing to its large volume variation during cycling and low intrinsic electrical conductivity.To mitigate these issues,free-standing N-doped porous carbon nanofibers sheathed pumpkin-like Si/C composites(Si/C-ZIF-8/CNFs)are designed and synthesized by electrospinning and carbonization methods,which present greatly enhanced electrochemical properties for lithium-ion battery anodes.This particular structure alleviates the volume variation,promotes the formation of stable solid electrolyte interphase(SEI)film,and improves the electrical conductivity.As a result,the as-obtained free-standing Si/C-ZIF-8/CNFs electrode delivers a high reversible capacity of 945.5 mAh g^(-1) at 0.2 A g^(-1) with a capacity retention of 64% for 150 cycles,and exhibits a reversible capacity of 538.6 mA h g^(-1) at 0.5 A g^(-1) over 500 cycles.Moreover,the full cell composed of a freestanding Si/C-ZIF-8/CNFs anode and commercial LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)(NCM)cathode shows a capacity of 63.4 mA h g^(-1) after 100 cycles at 0.2 C,which corresponds to a capacity retention of 60%.This rational design could provide a new path for the development of high-performance Si-based anodes.
基金support from the National Natural Science Foundation of China(Nos.22179022 and 22109023)the Industry-University-Research Joint Innovation Project of Fujian Province(No.2021H6006)+1 种基金the Award Program for Fujian Minjiang Scholar Professorshipthe Talent Fund Program of Fujian Normal University。
文摘Li metal anodes(LMAs)has attracted extensive research interest because of its extremely high theoretical capacity(3860 m Ah/g)at low redox potential(-3.04 V vs.standard hydrogen electrode).However,the extremely high chemical reactivity and the intrinsic“hostless”nature of LMAs bring about serious dendritic growth and dramatic volume change during the plating/strapping process,thus resulting in poor Coulombic efficiency,short lifespan,and severe safety concerns.Of various strategies,the construction of three-dimensional carbonaceous scaffolds for LMAs can substantially reduce the local current density,inhibit Li dendrite growth,and accommodate volume variation.Electrospinning is a simple yet effective strategy to fabricate carbon nanofibers(CNFs),which have been regarded as promising skeletons for LMAs,owing to their large surface areas,good electrical conductivity,and high porosity.In this Mini Review,we briefly introduce the fabrication of CNFs using electrospinning and the modification of CNFs.We highlight the recent advances in electrospun CNF skeletons for LMAs,including pure CNF and CNF-based composite scaffolds.Finally,we discuss the remaining challenges of electrospun CNF scaffolds for LMAs and provide possible solutions to push forward the advancement in this field.
基金financial support from the following sources: the National Natural Science Foundation of China (NSFC) (Grants 51607054, 51772073)Young Talent of Hebei Province (Nos. 70280011808, 70280016160250)+1 种基金Hebei Province Outstanding Youth Fund (A2018201019, A2017201082)Hebei Province Natural Science Fund (A2015201050)。
文摘In this work, a CoNxC active sites-rich three-dimensional porous carbon nanofibers network derived from bacterial cellulose and bimetal-ZIFs is prepared via a nucleation growth strategy and a pyrolysis process.The material displays excellent electrocatalytic activity for the oxygen reduction reaction, reaching a high limiting diffusion current density of -7.8 mA cm^(-2), outperforming metal–organic frameworks derived multifunctional electrocatalysts, and oxygen evolution reaction and hydrogen evolution reaction with low overpotentials of 380 and 107 mV, respectively. When the electrochemical properties are further evaluated, the electrocatalyst as an air cathode for Zn-air batteries exhibits a high cycling stability for63 h as well as a maximum power density of 308 mW cm^(-2), which is better than those for most Zn-air batteries reported to date. In addition, a power density of 152 mW cm^(-2) is provided by the solid-state Zn-air batteries, and the cycling stability is outstanding for 24 h. The remarkable electrocatalytic properties are attributed to the synergistic effect of the 3 D porous carbon nanofibers network and abundant inserted CoNxC active sites, which enable the fast transmission of ions and mass and simultaneously provide a large contact area for the electrode/electrolyte.
基金the National Natural Science Foundation of China(51972270,51702262,51911530212,51872240,51672225,61805201)the China Postdoctoral Science Foundation(2018T111093,2018M643732,2018BSHYDZZ57)+3 种基金the Natural Science Foundation of Shaanxi Province(2020JZ-07)the Key Research and Development Program of Shaanxi Province(2019TSLGY07-03)the Fundamental Research Funds for the Central Universities(3102019JC005 and 3102019ghxm004)the Research Fund of the State Key Laboratory of Solidification Processing(NPU),China(2019-QZ-03).
文摘Onedimensional porous carbons bearing high surface areas and sufficient heteroatom doped functionalities are essential for advanced electrochemical energy storage devices,especially for developing freestanding film electrodes.Here we develop a porous,nitrogenenriched,freestanding hollow carbon nanofiber(PNFHCF)electrode material via filtration of polypyrrole(PPy)hollow nanofibers formed by in situ selfdegraded templateassisted strategy,followed by NH3assisted carbonization.The PNFHCF retains the freestanding film morphology that is composed of threedimensional networks from the entanglement of 1D nanofiber and delivers 3.7fold increase in specific surface area(592 m^(2)g^(-1))compared to the carbon without NH_(3)treatment(FHCF).In spite of the enhanced specific surface area,PNFHCF still exhibits comparable high content of surface N functionalities(8.8%,atom fraction)to FHCF.Such developed hierarchical porous structure without sacrificing N doping functionalities together enables the achievement of high capacity,highrate property and good cycling stability when applied as selfsupporting anode in lithiumion batteries,superior to those of FHCF without NH3 treatment.
