In this paper,a new resin called Resin M for imparting antifelting properties to wool fabricshas been studied.Resin M may be used by aqueous oxidative/polymer technique.It is provedthat Oxidant A/Resin M treatment can...In this paper,a new resin called Resin M for imparting antifelting properties to wool fabricshas been studied.Resin M may be used by aqueous oxidative/polymer technique.It is provedthat Oxidant A/Resin M treatment can satisfy the machine washable requirement formulated byI.W.S..Resin M is a good agent for antifelting treatment of wool fabrics with proper pretreatment.Oxidant A/Resin M treatment has little influence on dyeing and moisture adsorption properties ofwool fibers.The pilling resistance of the treated fabrics is higher than that of the untreated ones.The strength and the handle of the treated fabrics have little been changed.According to thescanning electron microscope observations,it is recommended that the polymer encapsulation ofindividual fiber also plays an important role in the felting resistance of the treated fabrics though itis well known that the shrink resistance of the treated fabrics is believed to be due to the binding offibers.展开更多
Vanadium redox flow batteries(VRFBs)hold significant promise for large-scale energy storage applications.However,the sluggish reaction kinetics on the electrode surface considerably limit their performance.Implementat...Vanadium redox flow batteries(VRFBs)hold significant promise for large-scale energy storage applications.However,the sluggish reaction kinetics on the electrode surface considerably limit their performance.Implementation of efficient surface modification on carbon electrodes through an economically viable production method is crucial for the practical application of VRFBs.Herein,a nano-carbon layer with morphology of fine nanoparticles(<90 nm)and rich oxygen functional groups was constructed on carbon felts by unbalanced magnetron sputtering coupled with thermal treatment.This modified carbon felt served as both anode and cathode in cell,enabling an improved wettability of electrolyte and high reversibility of the active mass,and promoted kinetics of redox reactions.The optimized carbon felt,achieved through one hour of deposition(1C-CF),demonstrated outstanding electrochemical performance in a single cell.The cell exhibited a high energy efficiency of 82.4%at a current density of 100 m A cm^(-2)and maintained 71.8%at a high current density of 250 mA cm^(-2).Furthermore,the energy efficiency remained at 77.2%during long-term cycling(450 cycles)at a current density of 150 mA cm^(-2),indicating good electrode stability.Our results shed light on the surface design of carbon felt electrodes for the broad application interest of VRFB energy storage systems.展开更多
The scarcity of wettability,insufficient active sites,and low surface area of graphite felt(GF)have long been suppressing the performance of vanadium redox flow batteries(VRFBs).Herein,an ultra-homogeneous multipledim...The scarcity of wettability,insufficient active sites,and low surface area of graphite felt(GF)have long been suppressing the performance of vanadium redox flow batteries(VRFBs).Herein,an ultra-homogeneous multipledimensioned defect,including nano-scale etching and atomic-scale N,O codoping,was used to modify GF by the molten salt system.NH_(4)Cl and KClO_(3) were added simultaneously to the system to obtain porous N/O co-doped electrode(GF/ON),where KClO_(3) was used to ultra-homogeneously etch,and O-functionalize electrode,and NH4Cl was used as N dopant,respectively.GF/ON presents better electrochemical catalysis for VO_(2)+/VO_(2)+ and V3+/V2+ reactions than only O-functionalized electrodes(GF/O)and GF.The enhanced electrochemical properties are attributed to an increase in active sites,surface area,and wettability,as well as the synergistic effect of N and O,which is also supported by the density functional theory calculations.Further,the cell using GF/ON shows higher discharge capacity,energy efficiency,and stability for cycling performance than the pristine cell at 140 mA cm^(−2) for 200 cycles.Moreover,the energy efficiency of the modified cell is increased by 9.7% from 55.2% for the pristine cell at 260 mA cm^(−2).Such an ultra-homogeneous etching with N and O co-doping through“boiling”molten salt medium provides an effective and practical application potential way to prepare superior electrodes for VRFB.展开更多
MXene,a transition metal carbide/nitride,has been prominent as an ideal electrochemical active material for supercapacitors.However,the low MXene load limits its practical applications.As environmental concerns and su...MXene,a transition metal carbide/nitride,has been prominent as an ideal electrochemical active material for supercapacitors.However,the low MXene load limits its practical applications.As environmental concerns and sustainable development become more widely recognized,it is necessary to explore a greener and cleaner technology to recycle textile by-products such as cotton.The present study proposes an effective 3D fabrication method that uses MXene to fabricate waste denim felt into ultralight and flexible supercapacitors through needling and carbonization.The 3D structure provided more sites for loading MXene onto Z-directional fiber bundles,resulting in more efficient ion exchange between the electrolyte and electrodes.Furthermore,the carbonization process removed the specific adverse groups in MXenes,further improving the specific capacitance,energy density,power density and electrical conductivity of supercapacitors.The electrodes achieve a maximum specific capacitance of 1748.5 mF cm-2 and demonstrate remarkable cycling stability maintaining more than 94%after 15,000 galvanostatic charge/discharge cycles.Besides,the obtained supercapacitors present a maximum specific capacitance of 577.5 mF cm^(-2),energy density of 80.2μWh cm^(-2)and power density of 3 mW cm^(-2),respectively.The resulting supercapacitors can be used to develop smart wearable power devices such as smartwatches,laying the foundation for a novel strategy of utilizing waste cotton in a high-quality manner.展开更多
Polysulfide/ferricyanide flow batteries(S/Fe RFBs),with the advantages of abundant earth reservation low cost,high safety,and environmental friendliness,have attracted significant interest and demonstrated noteworthy ...Polysulfide/ferricyanide flow batteries(S/Fe RFBs),with the advantages of abundant earth reservation low cost,high safety,and environmental friendliness,have attracted significant interest and demonstrated noteworthy potential for practical applications.However,the battery performance,including the energy efficiency(EE),voltage efficiency(VE),and power density of the S/Fe RFBs remains low owing to the slow redox kinetics of polysulfide ions.To address these concerns,WS_(2)was selected as the booster and deposited on a commercial carbon felt electrode(WS_(2)-CF)to stimulate the redox reactions of polysulfide ions.With better hydrophilicity and smaller charge-transfer resistance,WS_(2)-CF exhibits enhanced electrochemical activity toward polysulfide redox reactions.Consequently,the battery performance of S/Fe RFB with WS_(2)-CF as the anode has been improved,with EE of 84%,VE of 84%,and a peak power density of 175.7 mW·cm^(-2),which are all higher than the cell only with the bare carbon felt(CF)as electrodes(76%,77%and 155.8 mW·cm^(-2),respectively).Furthermore,the cycling life of the S/Fe RFB with WS_(2)-CF has been prolonged to 2200 cycles with a capacity retention of 96% a 40 mA·cm^(-2)because of the good stability of WS_(2)-CF as the anode.Contrarily,under the same conditions,the S/Fe RFB without WS_(2)-CF terminated after 1500 cycles with a fast capacity decay.The successful utilization of WS_(2)as a booster on an electrode provides an efficient strategy for obtaining advanced S/Fe RFBs for practical applications.展开更多
Sodium(Na)metal stands out as a highly promising anode material for highenergy-density Na batteries owing to its abundant resources and exceptional theoretical capacity at low redox potential.Nevertheless,the uncontro...Sodium(Na)metal stands out as a highly promising anode material for highenergy-density Na batteries owing to its abundant resources and exceptional theoretical capacity at low redox potential.Nevertheless,the uncontrolled growth of Na dendrites and the accompanying volumetric changes during the plating/stripping process lead to safety concerns and poor electrochemical performances.This study introduces nitrogen and oxygen co-doped carbon nanofiber networks wrapped carbon felt(NO-CNCF),serving as Na deposition skeletons to facilitate a highly reversible Na metal anode.The NO-CNCF framework with uniformly distributed“sodiophilic”functional groups,nanonetwork protuberances,and cross-linked network scaffold structure can avoid charge accumulation and facilitate the dendrite-free Na deposition.Benefiting from these features,the NO-CNCF@Na symmetrical cells demonstrate notable enhancements in cycling stability,achieving 4000 h cycles at 1mA cm^(−2) for 1 mAh cm^(−2) and 2400 h cycles at 2mA cm^(−2) for 2 mAh cm^(−2) with voltage overpotential of approximately 6 and 10 mV,respectively.Furthermore,the NVP//NO-CNCF@Na full cells achieve stable cycling performance and favorable rate capability.This investigation offers novel insights into fabricating a“sodiophilic”matrix with a multistage structure toward high-performance Na metal batteries.展开更多
Fabrication, characterization and performance of a porous metal-fiber sintered felt （PMFSF） based on multi-tooth cutting and solid-phase sintering were studied. The PMFSF was used as the anodic methanol barrier in a...Fabrication, characterization and performance of a porous metal-fiber sintered felt （PMFSF） based on multi-tooth cutting and solid-phase sintering were studied. The PMFSF was used as the anodic methanol barrier in a passive air-breathing direct methanol fuel cell to mitigate the effects of methanol crossover. Compared with the commercial SUS316L felt made of bundle-drawn fibers, this self-made PMFSF has larger pore diameter, polarized pore distribution, irregular fiber shape, rougher surface, lower mass flow resistance and evident hydrophobicity. The results reveal that the use of a PMFSF significantly enhances the cell performance since it helps to maintain a balance between the reactant and product management while depressing methanol crossover. The PMFSF with a porosity of 70% yields the highest cell performance at a methanol concentration of 4 mol/L.展开更多
Scouring of raw wool is a chemical treatment that needs a high amount of detergents, alkalis and water. Effluents produced by this treatment are extremely polluted with chemicals and impurities washed out from the fib...Scouring of raw wool is a chemical treatment that needs a high amount of detergents, alkalis and water. Effluents produced by this treatment are extremely polluted with chemicals and impurities washed out from the fibers. It is well known that the ultrasound washing can remove effectively different substances from the textile surfaces even without surfactants due to the cavitations occurring at certain parameters of the ultrasound field. On the other side water treatments of wool combined with mechanical agitation provoked felting which can impair the quality of wool materials. Felting itself depends not only on the parameters of water treatments but also on the structure of wool cuticle. Partial hydrolysis of the cuticle with some proteases can decrease considerably the wool felting. The aim of this work is to study the possibility of applying the ultrasound at the process of raw wool scouring and the influence of proteases on the felting properties of wool at these conditions. It has been found out that ultrasound environment applied does not impair the specific activity of enzyme auxiliaries used and leads to increasing of their effect on the surface of wool fibers. Thus the scouring process studied could be used for developing of a technology producing lower amount and less polluted effluents.展开更多
Developing non-noble-metal oxygen evolution reaction(OER) electrocatalysts with high performance is critical to electrocatalytic water splitting. In this work, we fabricated Co Fe-layered double hydroxide(LDH) nanowir...Developing non-noble-metal oxygen evolution reaction(OER) electrocatalysts with high performance is critical to electrocatalytic water splitting. In this work, we fabricated Co Fe-layered double hydroxide(LDH) nanowire arrays on graphite felt(Co Fe-LDH/GF) via a hydrothermal method. The Co Fe-LDH/GF, as a robust integrated 3 D OER anode, exhibits excellent catalytic activity with the need of low overpotential of 252 and 285 mV to drive current densities of 10 and 100 mA/cm^(2) in 1.0 mol/L KOH, respectively. In addition, it also maintains electrochemical durability for at least 24 h. This work would open up avenues for the development of GF like attractive catalyst supports for oxygen evolution applications.展开更多
Advanced zinc-cerium redox flow battery（ZCRFB） is a large-scale energy storage system which plays a significant role in the application of new energy sources. The requirement of superior cathode with high acitivity ...Advanced zinc-cerium redox flow battery（ZCRFB） is a large-scale energy storage system which plays a significant role in the application of new energy sources. The requirement of superior cathode with high acitivity and fast ion diffusion is a hierarchical porous structure, which was synthesized in this work by a method in which both hard template and soft template were used. The structure and the performance of the cathode prepared here were characterized and evaluated by a variety of techniques such as scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, X-ray photoelectron spectroscopy（XPS）, cyclic voltammetry（CV）, linear sweep voltammetry（LSV）, and chronoamperometry（CA）. There were mainly three types of pore size within the hierarchical porous carbon： 2 μm, 80 nm, and 10 nm. The charge capacity of the cell using hierarchical porous carbon（HPC） as positive electrode was obviously larger than that using carbon felt; the former was 665.5 mAh with a coulombic efficiency of 89.0% and an energy efficiency of 79.0%, whereas the latter was 611.1 mAh with a coulombic efficiency of 81.5% and an energy efficiency of 68.6%. In addition, performance of the ZCRFB using HPC as positive electrode showed a good stability over 50 cycles.These results showed that the hierarchical porous carbon was superior over the carbon felt for application in ZCRFB.展开更多
Electro-oxidation of Ce （ Ⅲ ） to Ce （ Ⅳ ） in parallel plate flow type electrolyzer divided with cation exchange membrane was carried out in nitric acid media at carbon felt anode under galvanostatic conditions. ...Electro-oxidation of Ce （ Ⅲ ） to Ce （ Ⅳ ） in parallel plate flow type electrolyzer divided with cation exchange membrane was carried out in nitric acid media at carbon felt anode under galvanostatic conditions. Carbon felt was used as an anode for its high specific surface area and high oxygen evolution overpotential. Pt coated Ti plates were used as cathode and anode current feeder. The oxidation of 1 mol· L^-1 Ce（ Ⅲ ） solution in 2 mol· L^- 1 HNO3 was proceeding with a high current efficiency （92%） until about 80% of Ce（ Ⅲ ） was oxidized. Then, oxygen evolution, accompanied by terminal voltage jump, took place, lowering current efficiency. Ce（ Ⅲ ） was oxidized up to 90% with current efficiency of 62%. In this mode, strong carbon felt anode oxidation was observed. The wear out of carbon felt was 46% in six consequent runs （6 h of operation）. After each run, carbon felt surface had to be renewed with slightly alkaline solution to remove carbon oxidation products and ensure regular operational conditions. When anode surface was blocked, oxygen evolution took place from the beginning of electrolysis due to higher actual current density. The wear out of carbon felt anode could be minimized by means of oxygen evolution prevention. In the case when electrolysis had been stopped before oxygen evolution started （at Ce（ Ⅳ ） conversion of about 80% ）, the wear out of anode was less than 2% during 6 consequent runs （4 h of operation）.展开更多
Surface electropositivity and low internal resistance are important factors to improve the anode performance in microbial fuel cells (MFCs). Nitrogen doping is an effective way for the modification of traditional carb...Surface electropositivity and low internal resistance are important factors to improve the anode performance in microbial fuel cells (MFCs). Nitrogen doping is an effective way for the modification of traditional carbon materials. In this work, heat treatment and melamine were used to modify carbon felts to enhance electrogenesis capacity of MFCs. The modified carbon felts were characterized using X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), atomic force microscopy (AFM) and malvern zeta potentiometer. Results show that the maximum power densities under heat treatment increase from 276.1 to 423.4 mW/m(2) (700 degrees C) and 461.5 mW/m(2) (1200 degrees C) and further increase to 472.5 mW/m(2) (700 degrees C) and 515.4 mW/m(2) (1200 degrees C) with the co-carbonization modification of melamine. The heat treatment reduces the material resistivity, improves the zeta potential which is beneficial to microbial adsorption and electron transfer. The addition of melamine leads to the higher content of surface pyridinic and quaternary nitrogen and higher zeta potential. It is related to higher MFCs performance. Generally, the melamine modification at high temperature increases the feasibility of carbon felt as MFCs's anode materials. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.展开更多
The recent development of portable electronics promotes the growing demand for flexible energy storage devices. Supercapacitors are promising candidates due to their high power density. Therefore, flexible supercapaci...The recent development of portable electronics promotes the growing demand for flexible energy storage devices. Supercapacitors are promising candidates due to their high power density. Therefore, flexible supercapacitors are desired. Here, the porous activated carbon felts(ACFs) with exfoliated graphene nanosheets and rich oxygen-containing groups were fabricated by a facile thermal treatment strategy.Such ACFs can act as the flexible electrodes of all-solid-state supercapacitors directly without the use of binder and conductive materials. They exhibit excellent electrochemical properties, such as high specific areal capacitance, superior rate ability and long-term cycling stability. Moreover, the fabricated flexible all-solid-state supercapacitors based on ACFs deliver stable electrochemical performance under different bending states.展开更多
A phosphorous-doped graphite felt(PGF) is fabricated and examined as electrode for vanadium flow battery(VFB). P doping improves the electrolyte wettability of GF and induces more defect sites on its surface, resultin...A phosphorous-doped graphite felt(PGF) is fabricated and examined as electrode for vanadium flow battery(VFB). P doping improves the electrolyte wettability of GF and induces more defect sites on its surface, resulting in significantly enhanced activity and reversibility towards VO2^+/VO2^+ and V^2+/V3^+couples. VFB with PGF electrode demonstrates outstanding performance such as high-rate capability under 50–400 mA cm^-2, wide-temperature tolerance at-20 °C–60 °C, and excellent durability over 1000 charge–discharge cycles. These merits enable PGF a promising electrode for the next-generation VFB,which can operate at high-power and all-climate conditions.展开更多
Fabricating of high performance electrodes by a sustainable and cost effective method is essential to the development of vanadium redox flow batteries(VRFBs).In this work,an effective strategy is proposed to deposit c...Fabricating of high performance electrodes by a sustainable and cost effective method is essential to the development of vanadium redox flow batteries(VRFBs).In this work,an effective strategy is proposed to deposit carbon nanoparticles on graphite felts by hydrothermal carbonization method.This in-situ method minimizes the drop off and aggregation of carbon nanoparticles during electrochemical testing.Such integration of felts and hydrothermal carbons(HTC)produces a new electrode that combines the outstanding electrical conductivity of felts with the effective redox active sites provided by the HTC coating layer.The presence of the amorphous carbon layers on the felts is found to be able to promote the mass/charge transfer,and create oxygenated/nitrogenated active sites and hence enhances wettability.Consequently,the most optimized electrode based on a rational approach delivers an impressive electrochemical performance toward VRFBs in wide range of current densities from 200 to 500 mAcm^-2.The voltage efficiency(VE)of GFs-HTC is much higher than the VEs of the pristine GFs,especially at high current densities.It exhibits a 4.18 times increase in discharge capacity over the pristine graphite felt respectively,at a high current density of 400 mAcm^-2.The enhanced performance is attributed to the abundant active sites from amorphous hydrothermal carbon,which facilitates the fast electrochemical kinetics of vanadium redox reactions.This work evidences that the glucose-derived hydrothermal carbons as energy storage booster hold great promise in practical VRFBs application.展开更多
Developing excellent absorption-dominant electromagnetic interference(EMI)shielding composites is an urgent demand for the rapid development of 5 G technology and electronic equipment.Herein,a simple strategy is emplo...Developing excellent absorption-dominant electromagnetic interference(EMI)shielding composites is an urgent demand for the rapid development of 5 G technology and electronic equipment.Herein,a simple strategy is employed to fabricate carbon nanotubes-polypropylene fibers(CP)/polypropylene-glass fibers felt(PGFF)/Fe 3 O 4 composites with superior EMI shielding effectiveness and low reflection due to the magnetic-conductive bi-gradient structure which is naturally formed by deposition during the vacuum-assisted filtration process.The difference in dimensionality between one-dimensional CNT with outstand-ing electrical conductivity and zero-dimensional magnetic Fe 3 O 4 nanoparticles is the theoretical basis for the successful construction of the magnetic-conductive bi-gradient structure in a gap-rich PGFF matrix that endows the composites with“absorb-reflect-reabsorb”EMI shieldingmechanism.Whentheelectro-magnetic waves are incident from the magnetic layer,the EMI shielding effectiveness(SE)reaches 48.9 dB as the weight percentage of the conductive layer increases,more importantly,the reflection coefficients are reduced by more than 0.32 compared with that of another incident pattern.What’s more,the re-sultant composites exhibit an outstanding signal shielding function in the application.This work paves a convenient pathway for designing a magnetic-conductive bi-gradient structure and efficient absorbing EMI shielding composites applied in the next-generated electronic information and communication field.展开更多
Electrode materials with good redox kinetics,excellent mass transfer characteristics and ultra-high stability play a crucial role in reducing the life-cycle cost and prolonging the maintenance-free time of the vanadiu...Electrode materials with good redox kinetics,excellent mass transfer characteristics and ultra-high stability play a crucial role in reducing the life-cycle cost and prolonging the maintenance-free time of the vanadium flow batteries(VFB).Herein,a nitrogen-doped porous graphite felt electrode(N-PGF)is proposed by growing ZIF-67 nanoparticles on carbon fibers and then calcinating and acid etching.The multi-scale structure of“carbon fiber gap(electrolyte flow),micro/nano pore(active species diffusion)and Nitrogen active center(reaction site)”in N-PGF electrode effectively increases the catalytic sites and promotes mass transfer characteristics.Reasonable electrode design makes the battery show excellent rate performance and ultra-high cycling stability.The peak power density of the battery reaches 1006 mW cm^(-2).During 1000 cycles at 150 mA cm^(-2),the average discharge capacity and average discharge energy of N-PGF increase substantially by 11.6%and 23.4%compared with the benchmark thermal activated graphite felt,respectively.More excitingly,after ultra-long term(5000 cycles)operation at an ultra-high current density(300 mA cm^(-2)),N-PGF exhibits an unprecedented energy efficiency retention(99.79%)and electrochemical performance stability.展开更多
Vanadium flow battery （VFB） is a fast going and promising system for large-scale stationary energy stor- age. However, drawbacks such as low power density and narrow temperature window caused by poor catalytic activ...Vanadium flow battery （VFB） is a fast going and promising system for large-scale stationary energy stor- age. However, drawbacks such as low power density and narrow temperature window caused by poor catalytic activity of graphite felt （GF） electrodes limit its worldwide application. In this paper, bismuth, as a low-cost, no-toxic and high-activity electrocatalyst, is used to modify the thermal activated GF （TGF） via a facile hydrothermal method. Bismuth can effectively inhibit the side reaction of hydrogen evolution in wide temperature range, while promoting the V2＋/V3＋ redox reaction. As a result, the VFB assembled with Bi/TGF as negative electrode demonstrates outstanding rate performance under the current density up to 400 mAcm-2, as well as a long-term stability over 600 charging/discharging cycles at a high cur- rent density of 150mA cm-2. Moreover, it also shows excellent temperature adaptability from -10 ℃ to 50 ℃ and high durability for life test at the temperature of 50 ℃.展开更多
Vanadium redox flow batteries(VRFBs)are one of the most promising energy storage systems owing to their safety,efficiency,flexibility and scalability.However,the commercial viability of VRFBs is still hindered by the ...Vanadium redox flow batteries(VRFBs)are one of the most promising energy storage systems owing to their safety,efficiency,flexibility and scalability.However,the commercial viability of VRFBs is still hindered by the low electrochemical performance of the available carbon-based electrodes.Defect engineering is a powerful strategy to enhance the redox catalytic activity of carbon-based electrodes for VRFBs.In this paper,uniform carbon defects are introduced on the surfaces of carbon felt(CF)electrode by Ar plasma etching.Together with a higher specific surface area,the Ar plasma treated CF offers additional catalytic sites,allowing faster and more reversible oxidation/reduction reactions of vanadium ions.As a result,the VRFB using plasma treated electrode shows a power density of 1018.3 mW/cm^(2),an energy efficiency(EE)of 84.5%,and the EE remains stable over 1000 cycles.展开更多
文摘In this paper,a new resin called Resin M for imparting antifelting properties to wool fabricshas been studied.Resin M may be used by aqueous oxidative/polymer technique.It is provedthat Oxidant A/Resin M treatment can satisfy the machine washable requirement formulated byI.W.S..Resin M is a good agent for antifelting treatment of wool fabrics with proper pretreatment.Oxidant A/Resin M treatment has little influence on dyeing and moisture adsorption properties ofwool fibers.The pilling resistance of the treated fabrics is higher than that of the untreated ones.The strength and the handle of the treated fabrics have little been changed.According to thescanning electron microscope observations,it is recommended that the polymer encapsulation ofindividual fiber also plays an important role in the felting resistance of the treated fabrics though itis well known that the shrink resistance of the treated fabrics is believed to be due to the binding offibers.
基金supported by National Natural Science Foundation of China(U21B2057)。
文摘Vanadium redox flow batteries(VRFBs)hold significant promise for large-scale energy storage applications.However,the sluggish reaction kinetics on the electrode surface considerably limit their performance.Implementation of efficient surface modification on carbon electrodes through an economically viable production method is crucial for the practical application of VRFBs.Herein,a nano-carbon layer with morphology of fine nanoparticles(<90 nm)and rich oxygen functional groups was constructed on carbon felts by unbalanced magnetron sputtering coupled with thermal treatment.This modified carbon felt served as both anode and cathode in cell,enabling an improved wettability of electrolyte and high reversibility of the active mass,and promoted kinetics of redox reactions.The optimized carbon felt,achieved through one hour of deposition(1C-CF),demonstrated outstanding electrochemical performance in a single cell.The cell exhibited a high energy efficiency of 82.4%at a current density of 100 m A cm^(-2)and maintained 71.8%at a high current density of 250 mA cm^(-2).Furthermore,the energy efficiency remained at 77.2%during long-term cycling(450 cycles)at a current density of 150 mA cm^(-2),indicating good electrode stability.Our results shed light on the surface design of carbon felt electrodes for the broad application interest of VRFB energy storage systems.
基金supported by the National Natural Science Foundation of China(No.51872090)Natural Science Foundation of Hebei Province(No.E2019209433,E2022209158)Colleges and Universities in Hebei Province Science and Technology Research Project(No.JZX2024026).
文摘The scarcity of wettability,insufficient active sites,and low surface area of graphite felt(GF)have long been suppressing the performance of vanadium redox flow batteries(VRFBs).Herein,an ultra-homogeneous multipledimensioned defect,including nano-scale etching and atomic-scale N,O codoping,was used to modify GF by the molten salt system.NH_(4)Cl and KClO_(3) were added simultaneously to the system to obtain porous N/O co-doped electrode(GF/ON),where KClO_(3) was used to ultra-homogeneously etch,and O-functionalize electrode,and NH4Cl was used as N dopant,respectively.GF/ON presents better electrochemical catalysis for VO_(2)+/VO_(2)+ and V3+/V2+ reactions than only O-functionalized electrodes(GF/O)and GF.The enhanced electrochemical properties are attributed to an increase in active sites,surface area,and wettability,as well as the synergistic effect of N and O,which is also supported by the density functional theory calculations.Further,the cell using GF/ON shows higher discharge capacity,energy efficiency,and stability for cycling performance than the pristine cell at 140 mA cm^(−2) for 200 cycles.Moreover,the energy efficiency of the modified cell is increased by 9.7% from 55.2% for the pristine cell at 260 mA cm^(−2).Such an ultra-homogeneous etching with N and O co-doping through“boiling”molten salt medium provides an effective and practical application potential way to prepare superior electrodes for VRFB.
基金The authors acknowledge the financial support from the National Natural Science Foundation of China(Nos.52073224,32201491)the Textile Vision Basic Research Program of China(No.J202110)+3 种基金the Scientific Research Project of Shaanxi Provincial Education Department,China(No.22JC035)the Advanced Manufacturing Technology Program of Xi’an Science and Technology Bureau,China(No.21XJZZ0019)the Research Fund for the Doctoral Program of Xi’an Polytechnic University(No.BS202053)the Youth Innovation Team of Shaanxi Universities and Institute of Flexible electronics and Intelligent Textile.
文摘MXene,a transition metal carbide/nitride,has been prominent as an ideal electrochemical active material for supercapacitors.However,the low MXene load limits its practical applications.As environmental concerns and sustainable development become more widely recognized,it is necessary to explore a greener and cleaner technology to recycle textile by-products such as cotton.The present study proposes an effective 3D fabrication method that uses MXene to fabricate waste denim felt into ultralight and flexible supercapacitors through needling and carbonization.The 3D structure provided more sites for loading MXene onto Z-directional fiber bundles,resulting in more efficient ion exchange between the electrolyte and electrodes.Furthermore,the carbonization process removed the specific adverse groups in MXenes,further improving the specific capacitance,energy density,power density and electrical conductivity of supercapacitors.The electrodes achieve a maximum specific capacitance of 1748.5 mF cm-2 and demonstrate remarkable cycling stability maintaining more than 94%after 15,000 galvanostatic charge/discharge cycles.Besides,the obtained supercapacitors present a maximum specific capacitance of 577.5 mF cm^(-2),energy density of 80.2μWh cm^(-2)and power density of 3 mW cm^(-2),respectively.The resulting supercapacitors can be used to develop smart wearable power devices such as smartwatches,laying the foundation for a novel strategy of utilizing waste cotton in a high-quality manner.
基金financially supported by the NationalNatural Science Foundation of China(No.22209015)Scientific Research Foundation of Hunan Provincial Education Department(Nos.21A0195 and 21C0215)100 Talented Team of Hunan Province(No.XiangZu[2016]91)。
文摘Polysulfide/ferricyanide flow batteries(S/Fe RFBs),with the advantages of abundant earth reservation low cost,high safety,and environmental friendliness,have attracted significant interest and demonstrated noteworthy potential for practical applications.However,the battery performance,including the energy efficiency(EE),voltage efficiency(VE),and power density of the S/Fe RFBs remains low owing to the slow redox kinetics of polysulfide ions.To address these concerns,WS_(2)was selected as the booster and deposited on a commercial carbon felt electrode(WS_(2)-CF)to stimulate the redox reactions of polysulfide ions.With better hydrophilicity and smaller charge-transfer resistance,WS_(2)-CF exhibits enhanced electrochemical activity toward polysulfide redox reactions.Consequently,the battery performance of S/Fe RFB with WS_(2)-CF as the anode has been improved,with EE of 84%,VE of 84%,and a peak power density of 175.7 mW·cm^(-2),which are all higher than the cell only with the bare carbon felt(CF)as electrodes(76%,77%and 155.8 mW·cm^(-2),respectively).Furthermore,the cycling life of the S/Fe RFB with WS_(2)-CF has been prolonged to 2200 cycles with a capacity retention of 96% a 40 mA·cm^(-2)because of the good stability of WS_(2)-CF as the anode.Contrarily,under the same conditions,the S/Fe RFB without WS_(2)-CF terminated after 1500 cycles with a fast capacity decay.The successful utilization of WS_(2)as a booster on an electrode provides an efficient strategy for obtaining advanced S/Fe RFBs for practical applications.
基金Talent Project of University and Research Institute of Jinan,Grant/Award Number:2020GXRC044Talent research project of Qilu University of Technology(Shandong Academy of Sciences),Grant/Award Number:2023RCKY161+3 种基金Shandong Provincial Key Laboratory of Biomass Gasification Technology,Qilu University of Technology(Shandong Academy of Sciences),Grant/Award Number:BG-KFX-01Science and Technology Project of Shandong Province,Grant/Award Number:WST2020010Natural Science Foundation of Shandong Province,Grant/Award Number:ZR2021QB138Science,Education and Industry Integration of Basic Research Projects of Qilu University of Technology(Shandong Academy of Sciences),Grant/Award Number:2023PX007。
文摘Sodium(Na)metal stands out as a highly promising anode material for highenergy-density Na batteries owing to its abundant resources and exceptional theoretical capacity at low redox potential.Nevertheless,the uncontrolled growth of Na dendrites and the accompanying volumetric changes during the plating/stripping process lead to safety concerns and poor electrochemical performances.This study introduces nitrogen and oxygen co-doped carbon nanofiber networks wrapped carbon felt(NO-CNCF),serving as Na deposition skeletons to facilitate a highly reversible Na metal anode.The NO-CNCF framework with uniformly distributed“sodiophilic”functional groups,nanonetwork protuberances,and cross-linked network scaffold structure can avoid charge accumulation and facilitate the dendrite-free Na deposition.Benefiting from these features,the NO-CNCF@Na symmetrical cells demonstrate notable enhancements in cycling stability,achieving 4000 h cycles at 1mA cm^(−2) for 1 mAh cm^(−2) and 2400 h cycles at 2mA cm^(−2) for 2 mAh cm^(−2) with voltage overpotential of approximately 6 and 10 mV,respectively.Furthermore,the NVP//NO-CNCF@Na full cells achieve stable cycling performance and favorable rate capability.This investigation offers novel insights into fabricating a“sodiophilic”matrix with a multistage structure toward high-performance Na metal batteries.
基金Projects(50930005,51075155)supported by the National Natural Science Foundation of ChinaProject(20100172110001)supported by PhD Programs Foundation of Ministry of Education of China
文摘Fabrication, characterization and performance of a porous metal-fiber sintered felt （PMFSF） based on multi-tooth cutting and solid-phase sintering were studied. The PMFSF was used as the anodic methanol barrier in a passive air-breathing direct methanol fuel cell to mitigate the effects of methanol crossover. Compared with the commercial SUS316L felt made of bundle-drawn fibers, this self-made PMFSF has larger pore diameter, polarized pore distribution, irregular fiber shape, rougher surface, lower mass flow resistance and evident hydrophobicity. The results reveal that the use of a PMFSF significantly enhances the cell performance since it helps to maintain a balance between the reactant and product management while depressing methanol crossover. The PMFSF with a porosity of 70% yields the highest cell performance at a methanol concentration of 4 mol/L.
文摘Scouring of raw wool is a chemical treatment that needs a high amount of detergents, alkalis and water. Effluents produced by this treatment are extremely polluted with chemicals and impurities washed out from the fibers. It is well known that the ultrasound washing can remove effectively different substances from the textile surfaces even without surfactants due to the cavitations occurring at certain parameters of the ultrasound field. On the other side water treatments of wool combined with mechanical agitation provoked felting which can impair the quality of wool materials. Felting itself depends not only on the parameters of water treatments but also on the structure of wool cuticle. Partial hydrolysis of the cuticle with some proteases can decrease considerably the wool felting. The aim of this work is to study the possibility of applying the ultrasound at the process of raw wool scouring and the influence of proteases on the felting properties of wool at these conditions. It has been found out that ultrasound environment applied does not impair the specific activity of enzyme auxiliaries used and leads to increasing of their effect on the surface of wool fibers. Thus the scouring process studied could be used for developing of a technology producing lower amount and less polluted effluents.
基金supported by the National Natural Science Foundation of China (No.22072015)。
文摘Developing non-noble-metal oxygen evolution reaction(OER) electrocatalysts with high performance is critical to electrocatalytic water splitting. In this work, we fabricated Co Fe-layered double hydroxide(LDH) nanowire arrays on graphite felt(Co Fe-LDH/GF) via a hydrothermal method. The Co Fe-LDH/GF, as a robust integrated 3 D OER anode, exhibits excellent catalytic activity with the need of low overpotential of 252 and 285 mV to drive current densities of 10 and 100 mA/cm^(2) in 1.0 mol/L KOH, respectively. In addition, it also maintains electrochemical durability for at least 24 h. This work would open up avenues for the development of GF like attractive catalyst supports for oxygen evolution applications.
基金supported by National Program on Key Basic Research Project of China(973 Program,2012CB215500)National Natural Science Foundation of China(21361010)
文摘Advanced zinc-cerium redox flow battery（ZCRFB） is a large-scale energy storage system which plays a significant role in the application of new energy sources. The requirement of superior cathode with high acitivity and fast ion diffusion is a hierarchical porous structure, which was synthesized in this work by a method in which both hard template and soft template were used. The structure and the performance of the cathode prepared here were characterized and evaluated by a variety of techniques such as scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, X-ray photoelectron spectroscopy（XPS）, cyclic voltammetry（CV）, linear sweep voltammetry（LSV）, and chronoamperometry（CA）. There were mainly three types of pore size within the hierarchical porous carbon： 2 μm, 80 nm, and 10 nm. The charge capacity of the cell using hierarchical porous carbon（HPC） as positive electrode was obviously larger than that using carbon felt; the former was 665.5 mAh with a coulombic efficiency of 89.0% and an energy efficiency of 79.0%, whereas the latter was 611.1 mAh with a coulombic efficiency of 81.5% and an energy efficiency of 68.6%. In addition, performance of the ZCRFB using HPC as positive electrode showed a good stability over 50 cycles.These results showed that the hierarchical porous carbon was superior over the carbon felt for application in ZCRFB.
文摘Electro-oxidation of Ce （ Ⅲ ） to Ce （ Ⅳ ） in parallel plate flow type electrolyzer divided with cation exchange membrane was carried out in nitric acid media at carbon felt anode under galvanostatic conditions. Carbon felt was used as an anode for its high specific surface area and high oxygen evolution overpotential. Pt coated Ti plates were used as cathode and anode current feeder. The oxidation of 1 mol· L^-1 Ce（ Ⅲ ） solution in 2 mol· L^- 1 HNO3 was proceeding with a high current efficiency （92%） until about 80% of Ce（ Ⅲ ） was oxidized. Then, oxygen evolution, accompanied by terminal voltage jump, took place, lowering current efficiency. Ce（ Ⅲ ） was oxidized up to 90% with current efficiency of 62%. In this mode, strong carbon felt anode oxidation was observed. The wear out of carbon felt was 46% in six consequent runs （6 h of operation）. After each run, carbon felt surface had to be renewed with slightly alkaline solution to remove carbon oxidation products and ensure regular operational conditions. When anode surface was blocked, oxygen evolution took place from the beginning of electrolysis due to higher actual current density. The wear out of carbon felt anode could be minimized by means of oxygen evolution prevention. In the case when electrolysis had been stopped before oxygen evolution started （at Ce（ Ⅳ ） conversion of about 80% ）, the wear out of anode was less than 2% during 6 consequent runs （4 h of operation）.
文摘Surface electropositivity and low internal resistance are important factors to improve the anode performance in microbial fuel cells (MFCs). Nitrogen doping is an effective way for the modification of traditional carbon materials. In this work, heat treatment and melamine were used to modify carbon felts to enhance electrogenesis capacity of MFCs. The modified carbon felts were characterized using X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), atomic force microscopy (AFM) and malvern zeta potentiometer. Results show that the maximum power densities under heat treatment increase from 276.1 to 423.4 mW/m(2) (700 degrees C) and 461.5 mW/m(2) (1200 degrees C) and further increase to 472.5 mW/m(2) (700 degrees C) and 515.4 mW/m(2) (1200 degrees C) with the co-carbonization modification of melamine. The heat treatment reduces the material resistivity, improves the zeta potential which is beneficial to microbial adsorption and electron transfer. The addition of melamine leads to the higher content of surface pyridinic and quaternary nitrogen and higher zeta potential. It is related to higher MFCs performance. Generally, the melamine modification at high temperature increases the feasibility of carbon felt as MFCs's anode materials. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.
基金supported by National Natural Science Foundation of China (Nos. 21573116, 51822205 and 21875121)Ministry of Science and Technology of China (No. 2017YFA0206701)+1 种基金Ministry of Education of China (No. B12015)the Young Thousand Talents Program
文摘The recent development of portable electronics promotes the growing demand for flexible energy storage devices. Supercapacitors are promising candidates due to their high power density. Therefore, flexible supercapacitors are desired. Here, the porous activated carbon felts(ACFs) with exfoliated graphene nanosheets and rich oxygen-containing groups were fabricated by a facile thermal treatment strategy.Such ACFs can act as the flexible electrodes of all-solid-state supercapacitors directly without the use of binder and conductive materials. They exhibit excellent electrochemical properties, such as high specific areal capacitance, superior rate ability and long-term cycling stability. Moreover, the fabricated flexible all-solid-state supercapacitors based on ACFs deliver stable electrochemical performance under different bending states.
基金supported by the National Natural Science Foundation of China(No.21576154)the Shenzhen Basic Research Project(Nos.JCYJ20170818115018000,JCYJ20170307154206288,JCYJ20170412170756603)
文摘A phosphorous-doped graphite felt(PGF) is fabricated and examined as electrode for vanadium flow battery(VFB). P doping improves the electrolyte wettability of GF and induces more defect sites on its surface, resulting in significantly enhanced activity and reversibility towards VO2^+/VO2^+ and V^2+/V3^+couples. VFB with PGF electrode demonstrates outstanding performance such as high-rate capability under 50–400 mA cm^-2, wide-temperature tolerance at-20 °C–60 °C, and excellent durability over 1000 charge–discharge cycles. These merits enable PGF a promising electrode for the next-generation VFB,which can operate at high-power and all-climate conditions.
基金supported by the Award Program for Fujian Minjiang Scholar Professorshipthe National Natural Science Foundation of China(21571035)。
文摘Fabricating of high performance electrodes by a sustainable and cost effective method is essential to the development of vanadium redox flow batteries(VRFBs).In this work,an effective strategy is proposed to deposit carbon nanoparticles on graphite felts by hydrothermal carbonization method.This in-situ method minimizes the drop off and aggregation of carbon nanoparticles during electrochemical testing.Such integration of felts and hydrothermal carbons(HTC)produces a new electrode that combines the outstanding electrical conductivity of felts with the effective redox active sites provided by the HTC coating layer.The presence of the amorphous carbon layers on the felts is found to be able to promote the mass/charge transfer,and create oxygenated/nitrogenated active sites and hence enhances wettability.Consequently,the most optimized electrode based on a rational approach delivers an impressive electrochemical performance toward VRFBs in wide range of current densities from 200 to 500 mAcm^-2.The voltage efficiency(VE)of GFs-HTC is much higher than the VEs of the pristine GFs,especially at high current densities.It exhibits a 4.18 times increase in discharge capacity over the pristine graphite felt respectively,at a high current density of 400 mAcm^-2.The enhanced performance is attributed to the abundant active sites from amorphous hydrothermal carbon,which facilitates the fast electrochemical kinetics of vanadium redox reactions.This work evidences that the glucose-derived hydrothermal carbons as energy storage booster hold great promise in practical VRFBs application.
基金supported by the Key Research Pro-gram of Zhejiang Province(No.2020C01010)the Natural Science Foundation of Zhejiang Province(No.LY20E030008)the Na-tional Natural Science Foundation of China(No.21504078).
文摘Developing excellent absorption-dominant electromagnetic interference(EMI)shielding composites is an urgent demand for the rapid development of 5 G technology and electronic equipment.Herein,a simple strategy is employed to fabricate carbon nanotubes-polypropylene fibers(CP)/polypropylene-glass fibers felt(PGFF)/Fe 3 O 4 composites with superior EMI shielding effectiveness and low reflection due to the magnetic-conductive bi-gradient structure which is naturally formed by deposition during the vacuum-assisted filtration process.The difference in dimensionality between one-dimensional CNT with outstand-ing electrical conductivity and zero-dimensional magnetic Fe 3 O 4 nanoparticles is the theoretical basis for the successful construction of the magnetic-conductive bi-gradient structure in a gap-rich PGFF matrix that endows the composites with“absorb-reflect-reabsorb”EMI shieldingmechanism.Whentheelectro-magnetic waves are incident from the magnetic layer,the EMI shielding effectiveness(SE)reaches 48.9 dB as the weight percentage of the conductive layer increases,more importantly,the reflection coefficients are reduced by more than 0.32 compared with that of another incident pattern.What’s more,the re-sultant composites exhibit an outstanding signal shielding function in the application.This work paves a convenient pathway for designing a magnetic-conductive bi-gradient structure and efficient absorbing EMI shielding composites applied in the next-generated electronic information and communication field.
基金supported by the National Natural Science Foundation of China(21576154)the Natural Science Foundation of Guangdong Province(2022A1515011999 and 2019A1515011955)the Shenzhen Basic Research Project(20200829101039001 and GXWD20201231165806004)。
文摘Electrode materials with good redox kinetics,excellent mass transfer characteristics and ultra-high stability play a crucial role in reducing the life-cycle cost and prolonging the maintenance-free time of the vanadium flow batteries(VFB).Herein,a nitrogen-doped porous graphite felt electrode(N-PGF)is proposed by growing ZIF-67 nanoparticles on carbon fibers and then calcinating and acid etching.The multi-scale structure of“carbon fiber gap(electrolyte flow),micro/nano pore(active species diffusion)and Nitrogen active center(reaction site)”in N-PGF electrode effectively increases the catalytic sites and promotes mass transfer characteristics.Reasonable electrode design makes the battery show excellent rate performance and ultra-high cycling stability.The peak power density of the battery reaches 1006 mW cm^(-2).During 1000 cycles at 150 mA cm^(-2),the average discharge capacity and average discharge energy of N-PGF increase substantially by 11.6%and 23.4%compared with the benchmark thermal activated graphite felt,respectively.More excitingly,after ultra-long term(5000 cycles)operation at an ultra-high current density(300 mA cm^(-2)),N-PGF exhibits an unprecedented energy efficiency retention(99.79%)and electrochemical performance stability.
基金financial support from the National Natural Science Foundation of China (No. 21576154)the Open Fund of The State Key Laboratory of Refractories and Metallurgy (No. G201809)the Shenzhen Basic Research Project (Nos. JCYJ20170412170756603 and JCYJ20170307152754218)
文摘Vanadium flow battery （VFB） is a fast going and promising system for large-scale stationary energy stor- age. However, drawbacks such as low power density and narrow temperature window caused by poor catalytic activity of graphite felt （GF） electrodes limit its worldwide application. In this paper, bismuth, as a low-cost, no-toxic and high-activity electrocatalyst, is used to modify the thermal activated GF （TGF） via a facile hydrothermal method. Bismuth can effectively inhibit the side reaction of hydrogen evolution in wide temperature range, while promoting the V2＋/V3＋ redox reaction. As a result, the VFB assembled with Bi/TGF as negative electrode demonstrates outstanding rate performance under the current density up to 400 mAcm-2, as well as a long-term stability over 600 charging/discharging cycles at a high cur- rent density of 150mA cm-2. Moreover, it also shows excellent temperature adaptability from -10 ℃ to 50 ℃ and high durability for life test at the temperature of 50 ℃.
基金Project(Xiang Zu [2016] 91) supported by the “100 Talented Teams” of Hunan Province,ChinaProject(2018RS3077) supported by the Huxiang High-level Talents Program,China+2 种基金Project(22002009) supported by the National Natural Science Foundation of ChinaProject(2021JJ40565) supported by the Natural Science Foundation of Hunan Province,ChinaProject(19C0054) supported by the Scientific Research Foundation of Hunan Provincial Education Department,China。
文摘Vanadium redox flow batteries(VRFBs)are one of the most promising energy storage systems owing to their safety,efficiency,flexibility and scalability.However,the commercial viability of VRFBs is still hindered by the low electrochemical performance of the available carbon-based electrodes.Defect engineering is a powerful strategy to enhance the redox catalytic activity of carbon-based electrodes for VRFBs.In this paper,uniform carbon defects are introduced on the surfaces of carbon felt(CF)electrode by Ar plasma etching.Together with a higher specific surface area,the Ar plasma treated CF offers additional catalytic sites,allowing faster and more reversible oxidation/reduction reactions of vanadium ions.As a result,the VRFB using plasma treated electrode shows a power density of 1018.3 mW/cm^(2),an energy efficiency(EE)of 84.5%,and the EE remains stable over 1000 cycles.
