Polarization and conductance losses are the fundamental dielectric attenuation mechanisms for graphene-based absorbers, but it is not fully understood in revealing the loss mechanism of affect graphene itself. For the...Polarization and conductance losses are the fundamental dielectric attenuation mechanisms for graphene-based absorbers, but it is not fully understood in revealing the loss mechanism of affect graphene itself. For the first time, the reduced graphene oxide(RGO) based absorbers are developed with regulatory absorption properties and the absorption mechanism of RGO is mainly originated from the carrier injection behavior of trace metal Fe nanosheets on graphene. Accordingly, the minimum reflection loss(RLmin) of Fe/RGO-2composite reaches-53.38 dB(2.45 mm), and the effective absorption bandwidth achieves 7.52 GHz(2.62 mm) with lower filling loading of 2 wt%. Using off-axis electron hologram testing combined with simulation calculation and carrier transport property experiments, we demonstrate here the carrier injection behavior from Fe to graphene at the interface and the induced charge accumulation and rearrangement, resulting in the increased interfacial and dipole polarization and the conductance loss. This work has confirmed that regulating the dielectric property of graphene itself by adding trace metals can not only ensure good impedance matching, but also fully exploit the dielectric loss ability of graphene at low filler content,which opens up an efficient way for designing lightweight absorbers and may be extended to other types materials.展开更多
Three-dimensional(3D)porous absorbents have attracted significant attention in the oily wastewater treatment technology due to their high porosity and elasticity.Given their amphiphilic surface,they have a propensity ...Three-dimensional(3D)porous absorbents have attracted significant attention in the oily wastewater treatment technology due to their high porosity and elasticity.Given their amphiphilic surface,they have a propensity to simultaneously absorb water and oil,which restricts their range of applications.In this study,a reduced graphene oxide and titanium dioxide nanocomposite(rGO/TiO_(2))was used to fabricate an ultra-hydrophobic melamine sponge(MS)through interfacial modification using a solution immersion technique.To further modify it,poly-dimethylsiloxane(PDMS)was grafted onto its surface to establish stronger covalent bonds with the composite.The water contact angle of the sponge(rGO/TiO_(2)/PDMS/MS)was 164.2°,which satisfies the condition for ultrahydrophobicity.The evidence of its water repellency was demonstrated by the Cassie-Baxter theory and the lotus leaf effect.As a result of the increased density of rGO/TiO_(2)/PDMS/MS,it recorded an initial capacity that was 2 g/g lower than the raw MS for crude oil absorption.The raw MS retained 53% of its initial absorption capacity after 20 cycles of absorption,while rGO/TiO_(2)/PDMS/MS retained 97%,suggesting good recyclability.Excellent oil and organic solvent recovery(90%-96%)was demonstrated by rGO/TiO_(2)/PDMS/MS in oil-water combinations.In a continuous separation system,it achieved a remarkable separation efficiency of 2.4×10^(6)L/(m^(3)·h),and in turbulent emulsion separation,it achieved a demulsification efficiency of 90%-91%.This study provides a practical substitute for massive oil spill cleaning.展开更多
Reduced graphene oxide(rGO)aerogels are emerging as very attractive scaffolds for high-performance electromagnetic wave absorption materials(EWAMs)due to their intrinsic conductive networks and intricate interior micr...Reduced graphene oxide(rGO)aerogels are emerging as very attractive scaffolds for high-performance electromagnetic wave absorption materials(EWAMs)due to their intrinsic conductive networks and intricate interior microstructure,as well as good compatibility with other electromagnetic(EM)components.Herein,we realized the decoration of rGO aerogel with Mo_(2)C nanoparticles by sequential hydrothermal assembly,freeze-drying,and high-temperature pyrolysis.Results show that Mo_(2)C nanoparticle loading can be easily controlled by the ammonium molybdate to glucose molar ratio.The hydrophobicity and thermal insulation of the rGO aerogel are effectively improved upon the introduction of Mo_(2)C nanoparticles,and more importantly,these nanoparticles regulate the EM properties of the rGO aerogel to a large extent.Although more Mo_(2)C nanoparticles may decrease the overall attenuation ability of the rGO aerogel,they bring much better impedance matching.At a molar ratio of 1:1,a desirable balance between attenuation ability and impedance matching is observed.In this context,the Mo_(2)C/r GO aerogel displays strong reflection loss and broad response bandwidth,even with a small applied thickness(1.7 mm)and low filler loading(9.0wt%).The positive effects of Mo_(2)C nanoparticles on multifunctional properties may render Mo_(2)C/r GO aerogels promising candidates for high-performance EWAMs under harsh conditions.展开更多
Promising room-temperature sodium-sulfur(RT Na-S)battery systems rely on purposely designed highperforming and low-cost electrode materials.Nevertheless,there are the challenges of irreversible dissolution and slow re...Promising room-temperature sodium-sulfur(RT Na-S)battery systems rely on purposely designed highperforming and low-cost electrode materials.Nevertheless,there are the challenges of irreversible dissolution and slow redox kinetics of NaPSs in the complete discharge of sulfur capacity.Herein,engineered CoMoO_(4)in reduced graphene oxide(CoMoO_(4)@rGO)is reported as a class of superior cathode hosts for RT Na-S batteries.The CoMoO_(4)@rGO matrix is designed to facilitate the reversible sodiation and desodiation of sulfur,considering the strong chemisorption between sulfur(and short-chain sodium sulfides)and CoMoO_(4),which alleviates the shuttle effect of sodium sulfides and accelerates the electrochemical reaction rate at RT.The obtained S/CoMoO_(4)@rGO cathode with~52%S loading exhibits a high capacity of520.1 mA h g^(-1)after 100 cycles at 0.1 A g^(-1).Moreover,an enhanced long-term performance at high current densities(212.2 mA h g^(-1)at 4 A g^(-1)over 1000 cycles)with high Coulombic efficiency(~100%)is also achieved.This work demonstrates a novel multifunctional additive for RT Na-S battery cathodes,which is expected to promote the long-waited development towards practical applications of RT Na-S batteries.展开更多
Practical applications of diverse flexible wearable electronics require electrochemical energy storage(EES)devices with multiple configurations.Moreover,to fabricate flexible EES devices with high energy density and s...Practical applications of diverse flexible wearable electronics require electrochemical energy storage(EES)devices with multiple configurations.Moreover,to fabricate flexible EES devices with high energy density and stability,organic integration from electrode design to device assembly is required.To address these challenges,a free-standing reduced graphene oxide(rGO)/carbon film with a unique sandwich structure has been designed via the assistance of vacuum-assistant filtration for lithium-ion capacitors(LICs).The graphene acts as not only a binder to construct a three-dimensional conductive network but also an active material to provide additional capacitive lithium storage sites,thus enabling fast ion/electron transport and improving the capacity.The designed rGO/hard carbon(rGO/HC)and rGO/activated carbon(rGO/AC)free-standing films exhibit enhanced specific capacities(513.7 mA h g^(-1)for rGO/HC and 102.8 mA h g^(-1)for rGO/AC)and excellent stability.Moreover,the integrated flexible quasi-solid-state rGO/AC//rGO/HC LIC devices possess a maximum energy density of 138.3 Wh kg^(-1),a high power density of 11 kW kg^(-1),and improved cycling performance(84.4%capacitance maintained after 10,000 cycles),superior to the AC//HC LIC(43.5%retention).Such a strategy enlightens the development of portable flexible LICs.展开更多
Exploring and designing a high-performance non-noble metal catalyst for hydrogen evolution reaction(HER)are crucial for the large-scale application of H2 by water electrolysis.Here,novel catalysts with NiMo nanopartic...Exploring and designing a high-performance non-noble metal catalyst for hydrogen evolution reaction(HER)are crucial for the large-scale application of H2 by water electrolysis.Here,novel catalysts with NiMo nanoparticles decorated on reduced graphene oxide(NiMo@r GO)synthesized by a two-step hydrothermal method were reported.Physical characterization results showed that the prepared NiMo@r GO-1 had an irregular lamellar structure,and the NiMo nanoparticles were uniformly dispersed on the rGO.NiMo@rGO-1 exhibited outstanding HER performance in an alkaline environment and required only 93 and 180 mV overpotential for HER in 1.0 M KOH solution to obtain current densities of-10 and-50 mA·cm^(-2),respectively.Stability tests showed that NiMo@rGO-1 had a certain operating stability for32 h.Under the same condition,the performance of NiMo@rGO-1 can be comparable with that of commercial Pt/C catalysts at high current density.The synergistic effect between NiMo particles and lamellate graphene can remarkably promote charge transfer in electrocatalytic reactions.As a result,NiMo@rGO-1 presented the advantages of high intrinsic activity,large specific surface area,and small electrical impedance.The lamellar graphene played a role in dispersion to prevent the aggregation of nanoparticles.The prepared NiMo@rGO-1 can be used in anion exchange membrane water electrolysis to produce hydrogen.This study provides a simple preparation method for efficient and low-cost water electrolysis to produce hydrogen in the future.展开更多
Combustion within small motors is key in the application-specific development of nanothermite-based micro-energetic systems. This study evaluates the performance of nanothermite mixtures in a converging-diverging nozz...Combustion within small motors is key in the application-specific development of nanothermite-based micro-energetic systems. This study evaluates the performance of nanothermite mixtures in a converging-diverging nozzle and an open tube. Mixtures were prepared using nano-aluminum(n-Al),potassium perchlorate(KClO_(4)), and different carbon nanomaterials(CNMs) including graphene-oxide(GO), reduced GO, carbon nanotubes(CNTs) and nanofibers(CNFs). The mixtures were packed at different densities and ignited by laser beam. Performance was measured using thrust measurement,high-speed imaging, and computational fluid dynamics modeling, respectively. Thrust, specific impulse(ISP), volumetric impulse(ISV), as well as normalized energy were found to increase notably with CNM content. Two distinctive reaction regimes(fast and slow) were observed in combustion of low and high packing densities(20% and 55%TMD), respectively. Total impulse(IFT) and ISPwere maximized in the 5%GO/Al/KClO_4 mixture, producing 7.95 m N·s and 135.20 s respectively at 20%TMD, an improvement of 57%compared to a GO-free sample(5.05 m N·s and 85.88 s). CFD analysis of the motors over predicts the thrust generated but trends in nozzle layout and packing density agree with those observed experimentally;peak force was maximized by reducing packing density and using an open tube. The numerical force profiles fit better for the nozzle cases than the open tube scenarios due to the rapid nature of combustion. This study reveals the potential of GO in improving oxygenated salt-based nanothermites,and further demonstrates their applicability for micro-propulsion and micro-energetic applications.展开更多
Interfacial solar water evaporation is a reliable way to accelerate water evaporation and contaminant remediation.Embracing the recent advance in photothermal technology,a functional sponge was prepared by coating a s...Interfacial solar water evaporation is a reliable way to accelerate water evaporation and contaminant remediation.Embracing the recent advance in photothermal technology,a functional sponge was prepared by coating a sodium alginate(SA)impregnated sponge with a surface layer of reduced graphene oxide(rGO)to act as a photothermal conversion medium and then subsequently evaluated for its ability to enhance Pb extraction from contaminated soil driven by interfacial solar evaporation.The SA loaded sponge had a Pb adsorption capacity of 107.4 mg g^(-1).Coating the top surface of the SA sponge with rGO increased water evaporation performance to 1.81 kg m^(-2)h^(-1)in soil media under one sun illumination and with a wind velocity of 2 m s^(-1).Over 12 continuous days of indoor evaporation testing,the Pb extraction efficiency was increased by 22.0%under 1 sun illumination relative to that observed without illumination.Subsequently,Pb extraction was further improved by 48.9%under outdoor evaporation conditions compared to indoor conditions.Overall,this initial work shows the significant potential of interfacial solar evaporation technologies for Pb contaminated soil remediation,which should also be applicable to a variety of other environmental contaminants.展开更多
We previously combined reduced graphene oxide(rGO)with gelatin-methacryloyl(GelMA)and polycaprolactone(PCL)to create an rGO-GelMA-PCL nerve conduit and found that the conductivity and biocompatibility were improved.Ho...We previously combined reduced graphene oxide(rGO)with gelatin-methacryloyl(GelMA)and polycaprolactone(PCL)to create an rGO-GelMA-PCL nerve conduit and found that the conductivity and biocompatibility were improved.However,the rGO-GelMA-PCL nerve conduits differed greatly from autologous nerve transplants in their ability to promote the regeneration of injured peripheral nerves and axonal sprouting.Extracellular vesicles derived from bone marrow mesenchymal stem cells(BMSCs)can be loaded into rGO-GelMA-PCL nerve conduits for repair of rat sciatic nerve injury because they can promote angiogenesis at the injured site.In this study,12 weeks after surgery,sciatic nerve function was measured by electrophysiology and sciatic nerve function index,and myelin sheath and axon regeneration were observed by electron microscopy,immunohistochemistry,and immunofluorescence.The regeneration of microvessel was observed by immunofluorescence.Our results showed that rGO-GelMA-PCL nerve conduits loaded with BMSC-derived extracellular vesicles were superior to rGO-GelMA-PCL conduits alone in their ability to increase the number of newly formed vessels and axonal sprouts at the injury site as well as the recovery of neurological function.These findings indicate that rGO-GelMA-PCL nerve conduits loaded with BMSC-derived extracellular vesicles can promote peripheral nerve regeneration and neurological function recovery,and provide a new direction for the curation of peripheral nerve defect in the clinic.展开更多
In this study,three-dimensional porous magnesium ferrite/titanium dioxide/reduced graphene oxide(Mg Fe_2O_(4)-GM/TiO_(2)/rGO(MGTG))was successfully synthesized via green and hydrothermal-supported co-precipitation met...In this study,three-dimensional porous magnesium ferrite/titanium dioxide/reduced graphene oxide(Mg Fe_2O_(4)-GM/TiO_(2)/rGO(MGTG))was successfully synthesized via green and hydrothermal-supported co-precipitation methods using the extract of Garcinia mangostana(G.mangostana)as a reducing agent.The characterization results indicate the successful formation of the nano/micro Mg Fe_(2)O_(4)(MFO)and TiO_(2) on the structure of the reduced graphene oxide(rGO),which can also act as efficient support,alleviating the agglomeration of the nano/micro MFO and TiO_(2).The synergic effects of the adsorption and photodegradation activity of the material were investigated according to the removal of crystal violet(CV)under ultraviolet light.The effects of catalyst dosage,CV concentration,and p H on the CV removal efficiency of the MGTG were also investigated.According to the results,the CV photodegradation of the MGTG-200 corresponded to the pseudo-first-order kinetic model.The reusability of the material after 10 cycles also showed a removal efficiency of 92%.This happened because the materials can easily be recollected using external magnets.In addition,according to the effects of different free radicals·O_(2)^(-),h^(+),and·OH on the photodegradation process,the photocatalysis mechanism of the MGTG was also thoroughly suggested.The antibacterial efficiency of the MGTG was also evaluated according to the inhibition of the Gram-positive bacteria strain Staphylococcus aureus(S.aureus).Concurrently,the antibacterial mechanism of the fabricated material was also proposed.These results confirm that the prepared material can be potentially employed in a wide range of applications,including wastewater treatment and antibacterial activity.展开更多
Lithium-sulfur(Li-S) batteries can provide far higher energy density than currently commercialized lithium ion batteries, but challenges remain before it they are used in practice.One of the challenges is the shuttle ...Lithium-sulfur(Li-S) batteries can provide far higher energy density than currently commercialized lithium ion batteries, but challenges remain before it they are used in practice.One of the challenges is the shuttle effect that originates from soluble intermediates, like lithium polysulfides. To address this issue, we report a novel laminar composite, N,O-carboxymethyl chitosan-reduced graphene oxide(CC-rGO), which is manufactured via the self-assembly of CC onto GO and subsequent reduction of GO under an extreme condition of 1 Pa and-50°C. The synthesized laminar CC-rGO composite is mixed with acetylene black(AB) and coated on a commercial polypropylene(PP) membrane, resulting in a separator(CC-rGO/AB/PP) that can not only completely suppress the polysulfides penetration, but also can accelerate the lithium ion transportation, providing a Li-S battery with excellent cyclic stability and rate capability. As confirmed by theoretic simulations, this unique feature of CC-rGO is attributed to its strong repulsive interaction to polysulfide anions and its benefit for fast lithium ion transportation through the paths paved by the heteroatoms in CC.展开更多
The main bottleneck against industrial utilization of sodium ion batteries(SIBs)is the lack of high-capacity electrodes to rival those of the benchmark lithium ion batteries(LIBs).Here in this work,we have developed a...The main bottleneck against industrial utilization of sodium ion batteries(SIBs)is the lack of high-capacity electrodes to rival those of the benchmark lithium ion batteries(LIBs).Here in this work,we have developed an economical method for in situ fabrication of nanocomposites made of crystalline few-layer graphene sheets loaded with ultrafine SnO_(2)nanocrystals,using short exposure of microwave to xerogel of graphene oxide(GO)and tin tetrachloride containing minute catalyzing dispersoids of chemically reduced GO(RGO).The resultant nanocomposites(SnO_(2)@MWG)enabled significantly quickened redox processes as SIB anode,which led to remarkable full anode-specific capacity reaching 538 mAh g^(−1)at 0.05 A g^(−1)(about 1.45 times of the theoretical capacity of graphite for the LIB),in addition to outstanding rate performance over prolonged charge–discharge cycling.Anodes based on the optimized SnO_(2)@MWG delivered stable performance over 2000 cycles even at a high current density of 5 A g^(−1),and capacity retention of over 70.4%was maintained at a high areal loading of 3.4 mg cm^(−2),highly desirable for high energy density SIBs to rival the current benchmark LIBs.展开更多
In order to ensure the operational reliability and infor-mation security of sophisticated electronic components and to protect human health,efficient electromagnetic interference(EMI)shielding materials are required t...In order to ensure the operational reliability and infor-mation security of sophisticated electronic components and to protect human health,efficient electromagnetic interference(EMI)shielding materials are required to attenuate electromagnetic wave energy.In this work,the cellulose solution is obtained by dissolving cotton through hydrogen bond driving self-assembly using sodium hydroxide(NaOH)/urea solution,and cellulose aerogels(CA)are prepared by gelation and freeze-drying.Then,the cellulose carbon aerogel@reduced graphene oxide aerogels(CCA@rGO)are prepared by vacuum impregnation,freeze-drying followed by thermal annealing,and finally,the CCA@rGO/polydimethylsiloxane(PDMS)EMI shielding composites are prepared by backfilling with PDMS.Owing to skin-core structure of CCA@rGO,the complete three-dimensional(3D)double-layer con-ductive network can be successfully constructed.When the loading of CCA@rGO is 3.05 wt%,CCA@rGO/PDMS EMI shielding composites have an excellent EMI shielding effectiveness(EMI SE)of 51 dB,which is 3.9 times higher than that of the co-blended CCA/rGO/PDMS EMI shielding composites(13 dB)with the same loading of fillers.At this time,the CCA@rGO/PDMS EMI shielding composites have excellent thermal stability(T_(HRI) of 178.3℃)and good thermal conductivity coefficient(λ of 0.65 W m^(-1) K^(-1)).Excellent comprehensive performance makes CCA@rGO/PDMS EMI shielding composites great prospect for applications in lightweight,flexible EMI shielding composites.展开更多
Two-dimensional(2D)nanomaterials are categorized as a new class of microwave absorption(MA)materials owing to their high specific surface area and peculiar electronic properties.In this study,2D WS2-reduced graphene o...Two-dimensional(2D)nanomaterials are categorized as a new class of microwave absorption(MA)materials owing to their high specific surface area and peculiar electronic properties.In this study,2D WS2-reduced graphene oxide(WS2-rGO)heterostructure nanosheets were synthesized via a facile hydrothermal process;moreover,their dielectric and MA properties were reported for the first time.Remarkably,the maximum reflection loss(RL)of the sample-wax composites containing 40 wt% WS2-rGO was-41.5 dB at a thickness of 2.7 mm;furthermore,the bandwidth where RL<-10 dB can reach up to 13.62 GHz(4.38-18 GHz).Synergistic mechanisms derived from the interfacial dielectric coupling and multiple-interface scattering after hybridization of WS2 with rGO were discussed to explain the drastically enhanced microwave absorption performance.The results indicate these lightweight WS2-rGO nanosheets to be potential materials for practical electromagnetic wave-absorbing applications.展开更多
A flexible asymmetric supercapacitor(ASC)based on a Co Al-layered double hydroxide(Co Al-LDH)electrode and a reduced graphene oxide(r GO) electrode was successfully fabricated. The Co Al-LDH electrode as a positive el...A flexible asymmetric supercapacitor(ASC)based on a Co Al-layered double hydroxide(Co Al-LDH)electrode and a reduced graphene oxide(r GO) electrode was successfully fabricated. The Co Al-LDH electrode as a positive electrode was synthesized by directly growing Co Al-LDH nanosheet arrays on a carbon cloth(CC)through a facile hydrothermal method, and it delivered a specific capacitance of 616.9 F g^(-1)at a current density of1 A g^(-1). The r GO electrode as a negative electrode was synthesized by coating r GO on the CC via a simple dipcoating method and revealed a specific capacitance of110.0 F g^(-1)at a current density of 2 A g^(-1). Ultimately,the advanced ASC offered a broad voltage window(1.7 V)and exhibited a high superficial capacitance of1.77 F cm^(-2)at 2 m A cm^(-2)and a high energy density of0.71 m Wh cm^(-2)at a power density of 17.05 m W cm^(-2),along with an excellent cycle stability(92.9% capacitance retention over 8000 charge–discharge cycles).展开更多
A kind of sandwich-like NiCo_2O_4/rGO/NiO heterostructure composite has been successfully anchored on nickel foam substrate via a three-step hydrothermal method with successive annealing treatment. The smart combinati...A kind of sandwich-like NiCo_2O_4/rGO/NiO heterostructure composite has been successfully anchored on nickel foam substrate via a three-step hydrothermal method with successive annealing treatment. The smart combination of NiCo_2O_4, reduced graphene oxide(rGO), and NiO nanostructure in the sandwich-like nano architecture shows a promising synergistic effect for supercapacitors with greatly enhanced electrochemical performance. For serving as supercapacitor electrode, the NiCo_2O_4/rGO/NiO heterostructure materials exhibit remarkable specific capacitance of 2644 mF cm^(-2)at current density of 1 mA cm^(-2),and excellent capacitance retentions of 97.5% after 3000 cycles. It is expected that the present heterostructure will be a promising electrode material for high-performance supercapacitors.展开更多
Objective This study was aimed to investigate the toxic effects of 3 nanomaterials, i.e. multi-walled carbon nanotubes (MWCNTs), graphene oxide (GO), and reduced graphene oxide (RGO), on zebrafish embryos. Metho...Objective This study was aimed to investigate the toxic effects of 3 nanomaterials, i.e. multi-walled carbon nanotubes (MWCNTs), graphene oxide (GO), and reduced graphene oxide (RGO), on zebrafish embryos. Methods The 2-h post-fertilization (hpf) zebrafish embryos were exposed to MWCNTs, GO, and RGO at different concentrations (1, 5, 10, 50, 100 mg/L) for 96 h. Afterwards, the effects of the 3 nanomateria on spontaneous movement, heart rate, hatching rate, length of larvae, mortality, and malformations Is were evaluated. Results Statistical analysis indicated that RGO significantly inhibited the hatching of zebrafish embryos. Furthermore, RGO and MWCNTs decreased the length of the hatched larvae at 96 hpf. No obvious morphological malformation or mortality was observed in the zebrafish embryos after exposure to the three nanomaterials. Conclusion MWCNTs, GO, and RGO were all toxic to zebrafish embryos to influence embryos hatching and larvae length. Although no obvious morphological malformation and mortality were observed in exposed zebrafish embryos, further studies on the toxicity of the three nanomaterials are still needed.展开更多
The high-energy lithium/sulfur(Li/S) battery has become a very popular topic of research in recent years due to its high theoretical capacity of 1672 m Ah/g. However, the polysulfide shuttle effect remains of great co...The high-energy lithium/sulfur(Li/S) battery has become a very popular topic of research in recent years due to its high theoretical capacity of 1672 m Ah/g. However, the polysulfide shuttle effect remains of great concern with a great number of publications dedicated to its mitigation. In this contribution, a three-dimensional(3D) reduced graphene oxide/activated carbon(RGO/AC) film, synthesized by a simple hydrothermal method and convenient mechanical pressing, is sandwiched between the separator and the sulfur-based cathode, acting as a functional interlayer to capture and trap polysulfide species. Consequently, the Li/S cell with this interlayer shows an impressive initial discharge capacity of 1078 m Ah/g and a reversible capacity of 655 m Ah/g even after 100 cycles. The RGO/AC interlayer impedes the movement of polysulfide while providing unimpeded channels for lithium ion mass transfer. Therefore, the RGO/AC interlayer with a well-designed structure represents strong potential for high-performance Li/S batteries.展开更多
Silver nanowire(Ag NW)has been considered as the promising building block for the fabrication of transparent electromagnetic interference(EMI)shielding films.However,the practical application of Ag NW-based EMI shield...Silver nanowire(Ag NW)has been considered as the promising building block for the fabrication of transparent electromagnetic interference(EMI)shielding films.However,the practical application of Ag NW-based EMI shielding films has been restricted due to the unsatisfactory stability of Ag NW.Herein,we proposed a reduced graphene oxide(rGO)decorated Ag NW film,which realizes a seamless integration of optical transparency,highly efficient EMI shielding,reliable durability and stability.The Ag NW constructs a highly transparent and conductive network,and the rGO provides additional conductive path,showing a superior EMI shielding effectiveness(SE)of 33.62 dB at transmittance of 81.9%.In addition,the top rGO layer enables the hybrid film with reliable durability and chemical stability,which can maintain 96%and 90%EMI SE after 1000 times bending cycles at radius of 2 mm and exposure in air for 80 days.Furthermore,the rGO/Ag NW films also possess fast thermal response and heating stability,making them highly applicable in wearable devices.The synergy of Ag NW and rGO grants the hybrid EMI shielding film multiple desired functions and meanwhile overcomes the shortcomings of Ag NW.This work provides a reference for preparing multifunctional integrated transparent EMI shielding film.展开更多
A new Fe3C-N-doped reduced graphene oxide(Fe3C-N-rGO)prepared by a facile method is used as a separator for high performance lithium-sulfur(Li-S)batteries.The Fe3C-N-rGO is coated on the surface of commercial polyprop...A new Fe3C-N-doped reduced graphene oxide(Fe3C-N-rGO)prepared by a facile method is used as a separator for high performance lithium-sulfur(Li-S)batteries.The Fe3C-N-rGO is coated on the surface of commercial polypropylene separator(Celgard 2400)close to the sulfur cathode.The special nanotubes are in-situ catalyzed by Fe3C nanoparticles.They could entrap lithium polysulfides(Li PSs)to restrain the shuttle effect and reduce the loss of active material.The battery with the modified separator and sulfur cathode shows an excellent cycle performance.It has a high rate performance,580.5 mAh/g at the high current rate of 4 C relative to 1075 mAh/g at 0.1 C.It also has an initial discharge capacity of 774.8 m Ah/g measured at 0.5 C and remains 721.8 mAh/g after 100 cycles with a high capacity retention of 93.2%.The outstanding performances are notable in recently reports with modified separator.展开更多
基金supported by National Natural Science Foundation of China (NSFC 52372041, 52302087, 51772060, 51672059 and 51621091)Heilongjiang Touyan Team Program+1 种基金the Fundamental Research Funds for the Central Universities (Grant No. HIT.OCEF.2021003)the Shanghai Aerospace Science and Technology Innovation Fund (SAST2022-60)。
文摘Polarization and conductance losses are the fundamental dielectric attenuation mechanisms for graphene-based absorbers, but it is not fully understood in revealing the loss mechanism of affect graphene itself. For the first time, the reduced graphene oxide(RGO) based absorbers are developed with regulatory absorption properties and the absorption mechanism of RGO is mainly originated from the carrier injection behavior of trace metal Fe nanosheets on graphene. Accordingly, the minimum reflection loss(RLmin) of Fe/RGO-2composite reaches-53.38 dB(2.45 mm), and the effective absorption bandwidth achieves 7.52 GHz(2.62 mm) with lower filling loading of 2 wt%. Using off-axis electron hologram testing combined with simulation calculation and carrier transport property experiments, we demonstrate here the carrier injection behavior from Fe to graphene at the interface and the induced charge accumulation and rearrangement, resulting in the increased interfacial and dipole polarization and the conductance loss. This work has confirmed that regulating the dielectric property of graphene itself by adding trace metals can not only ensure good impedance matching, but also fully exploit the dielectric loss ability of graphene at low filler content,which opens up an efficient way for designing lightweight absorbers and may be extended to other types materials.
基金supported by the Universiti Brunei Darussalam Research Funding(Grant No.UBD/OAVCRI/CRGWG(022)/171001).
文摘Three-dimensional(3D)porous absorbents have attracted significant attention in the oily wastewater treatment technology due to their high porosity and elasticity.Given their amphiphilic surface,they have a propensity to simultaneously absorb water and oil,which restricts their range of applications.In this study,a reduced graphene oxide and titanium dioxide nanocomposite(rGO/TiO_(2))was used to fabricate an ultra-hydrophobic melamine sponge(MS)through interfacial modification using a solution immersion technique.To further modify it,poly-dimethylsiloxane(PDMS)was grafted onto its surface to establish stronger covalent bonds with the composite.The water contact angle of the sponge(rGO/TiO_(2)/PDMS/MS)was 164.2°,which satisfies the condition for ultrahydrophobicity.The evidence of its water repellency was demonstrated by the Cassie-Baxter theory and the lotus leaf effect.As a result of the increased density of rGO/TiO_(2)/PDMS/MS,it recorded an initial capacity that was 2 g/g lower than the raw MS for crude oil absorption.The raw MS retained 53% of its initial absorption capacity after 20 cycles of absorption,while rGO/TiO_(2)/PDMS/MS retained 97%,suggesting good recyclability.Excellent oil and organic solvent recovery(90%-96%)was demonstrated by rGO/TiO_(2)/PDMS/MS in oil-water combinations.In a continuous separation system,it achieved a remarkable separation efficiency of 2.4×10^(6)L/(m^(3)·h),and in turbulent emulsion separation,it achieved a demulsification efficiency of 90%-91%.This study provides a practical substitute for massive oil spill cleaning.
基金supported by the China Postdoctoral Science Foundation(No.2021MD703944)the Fund of Science and Technology on Near-Surface Detection Laboratory(No.6142414211808)+1 种基金the Director Fund of State Key Laboratory of Pulsed Power Laser Technology(No.SKL2021ZR06)the National Natural Science Foundation of China(No.21776053)。
文摘Reduced graphene oxide(rGO)aerogels are emerging as very attractive scaffolds for high-performance electromagnetic wave absorption materials(EWAMs)due to their intrinsic conductive networks and intricate interior microstructure,as well as good compatibility with other electromagnetic(EM)components.Herein,we realized the decoration of rGO aerogel with Mo_(2)C nanoparticles by sequential hydrothermal assembly,freeze-drying,and high-temperature pyrolysis.Results show that Mo_(2)C nanoparticle loading can be easily controlled by the ammonium molybdate to glucose molar ratio.The hydrophobicity and thermal insulation of the rGO aerogel are effectively improved upon the introduction of Mo_(2)C nanoparticles,and more importantly,these nanoparticles regulate the EM properties of the rGO aerogel to a large extent.Although more Mo_(2)C nanoparticles may decrease the overall attenuation ability of the rGO aerogel,they bring much better impedance matching.At a molar ratio of 1:1,a desirable balance between attenuation ability and impedance matching is observed.In this context,the Mo_(2)C/r GO aerogel displays strong reflection loss and broad response bandwidth,even with a small applied thickness(1.7 mm)and low filler loading(9.0wt%).The positive effects of Mo_(2)C nanoparticles on multifunctional properties may render Mo_(2)C/r GO aerogels promising candidates for high-performance EWAMs under harsh conditions.
基金the support of the National Natural Science Foundation of China(51971146,51971147,52171218 and 52271222)the Shanghai Municipal Science and Technology Commission(21010503100 and 20ZR1438400)+3 种基金the Innovation Program of Shanghai Municipal EducationCommission(No.2019-01-07-00-07-E00015)the Shanghai Rising-Star Program(20QA1407100 and Yangfan Special Project:23YF1428900)the support of the Advanced Research and Technology Innovation Centre(ARTIC,Project Number ADT-RP2/A0005947-32-00)for research conducted by John Wang’s group。
文摘Promising room-temperature sodium-sulfur(RT Na-S)battery systems rely on purposely designed highperforming and low-cost electrode materials.Nevertheless,there are the challenges of irreversible dissolution and slow redox kinetics of NaPSs in the complete discharge of sulfur capacity.Herein,engineered CoMoO_(4)in reduced graphene oxide(CoMoO_(4)@rGO)is reported as a class of superior cathode hosts for RT Na-S batteries.The CoMoO_(4)@rGO matrix is designed to facilitate the reversible sodiation and desodiation of sulfur,considering the strong chemisorption between sulfur(and short-chain sodium sulfides)and CoMoO_(4),which alleviates the shuttle effect of sodium sulfides and accelerates the electrochemical reaction rate at RT.The obtained S/CoMoO_(4)@rGO cathode with~52%S loading exhibits a high capacity of520.1 mA h g^(-1)after 100 cycles at 0.1 A g^(-1).Moreover,an enhanced long-term performance at high current densities(212.2 mA h g^(-1)at 4 A g^(-1)over 1000 cycles)with high Coulombic efficiency(~100%)is also achieved.This work demonstrates a novel multifunctional additive for RT Na-S battery cathodes,which is expected to promote the long-waited development towards practical applications of RT Na-S batteries.
基金financially supported by the National Natural Science Foundation of China(52077207 and 51907193)the Key Research Program of Frontier Sciences,CAS(ZDBS-LY-JSC047)the Youth Innovation Promotion Association CAS(2020145)。
文摘Practical applications of diverse flexible wearable electronics require electrochemical energy storage(EES)devices with multiple configurations.Moreover,to fabricate flexible EES devices with high energy density and stability,organic integration from electrode design to device assembly is required.To address these challenges,a free-standing reduced graphene oxide(rGO)/carbon film with a unique sandwich structure has been designed via the assistance of vacuum-assistant filtration for lithium-ion capacitors(LICs).The graphene acts as not only a binder to construct a three-dimensional conductive network but also an active material to provide additional capacitive lithium storage sites,thus enabling fast ion/electron transport and improving the capacity.The designed rGO/hard carbon(rGO/HC)and rGO/activated carbon(rGO/AC)free-standing films exhibit enhanced specific capacities(513.7 mA h g^(-1)for rGO/HC and 102.8 mA h g^(-1)for rGO/AC)and excellent stability.Moreover,the integrated flexible quasi-solid-state rGO/AC//rGO/HC LIC devices possess a maximum energy density of 138.3 Wh kg^(-1),a high power density of 11 kW kg^(-1),and improved cycling performance(84.4%capacitance maintained after 10,000 cycles),superior to the AC//HC LIC(43.5%retention).Such a strategy enlightens the development of portable flexible LICs.
基金financially supported by the National Natural Science Foundation of China(No.22278125)。
文摘Exploring and designing a high-performance non-noble metal catalyst for hydrogen evolution reaction(HER)are crucial for the large-scale application of H2 by water electrolysis.Here,novel catalysts with NiMo nanoparticles decorated on reduced graphene oxide(NiMo@r GO)synthesized by a two-step hydrothermal method were reported.Physical characterization results showed that the prepared NiMo@r GO-1 had an irregular lamellar structure,and the NiMo nanoparticles were uniformly dispersed on the rGO.NiMo@rGO-1 exhibited outstanding HER performance in an alkaline environment and required only 93 and 180 mV overpotential for HER in 1.0 M KOH solution to obtain current densities of-10 and-50 mA·cm^(-2),respectively.Stability tests showed that NiMo@rGO-1 had a certain operating stability for32 h.Under the same condition,the performance of NiMo@rGO-1 can be comparable with that of commercial Pt/C catalysts at high current density.The synergistic effect between NiMo particles and lamellate graphene can remarkably promote charge transfer in electrocatalytic reactions.As a result,NiMo@rGO-1 presented the advantages of high intrinsic activity,large specific surface area,and small electrical impedance.The lamellar graphene played a role in dispersion to prevent the aggregation of nanoparticles.The prepared NiMo@rGO-1 can be used in anion exchange membrane water electrolysis to produce hydrogen.This study provides a simple preparation method for efficient and low-cost water electrolysis to produce hydrogen in the future.
基金financial funding from the Egyptian governmentthe financial funding from the NSERC Discovery grant。
文摘Combustion within small motors is key in the application-specific development of nanothermite-based micro-energetic systems. This study evaluates the performance of nanothermite mixtures in a converging-diverging nozzle and an open tube. Mixtures were prepared using nano-aluminum(n-Al),potassium perchlorate(KClO_(4)), and different carbon nanomaterials(CNMs) including graphene-oxide(GO), reduced GO, carbon nanotubes(CNTs) and nanofibers(CNFs). The mixtures were packed at different densities and ignited by laser beam. Performance was measured using thrust measurement,high-speed imaging, and computational fluid dynamics modeling, respectively. Thrust, specific impulse(ISP), volumetric impulse(ISV), as well as normalized energy were found to increase notably with CNM content. Two distinctive reaction regimes(fast and slow) were observed in combustion of low and high packing densities(20% and 55%TMD), respectively. Total impulse(IFT) and ISPwere maximized in the 5%GO/Al/KClO_4 mixture, producing 7.95 m N·s and 135.20 s respectively at 20%TMD, an improvement of 57%compared to a GO-free sample(5.05 m N·s and 85.88 s). CFD analysis of the motors over predicts the thrust generated but trends in nozzle layout and packing density agree with those observed experimentally;peak force was maximized by reducing packing density and using an open tube. The numerical force profiles fit better for the nozzle cases than the open tube scenarios due to the rapid nature of combustion. This study reveals the potential of GO in improving oxygenated salt-based nanothermites,and further demonstrates their applicability for micro-propulsion and micro-energetic applications.
基金H.Xu acknowledges the financial support from the Australian Research Council(FT190100485,DP220100583)P.W.acknowledge financial support from the China Scholarship Council for primary scholarships and from the Future Industries Institute for top up scholarships.All authors acknowledge the use of Microscopy Australia facilities located at the University of South Australia,infrastructure co-funded by the University of South Australia,the South Australian State Government,and the Australian Federal Government's National Collaborative Research Infrastructure Strategy(NCRIS)scheme.
文摘Interfacial solar water evaporation is a reliable way to accelerate water evaporation and contaminant remediation.Embracing the recent advance in photothermal technology,a functional sponge was prepared by coating a sodium alginate(SA)impregnated sponge with a surface layer of reduced graphene oxide(rGO)to act as a photothermal conversion medium and then subsequently evaluated for its ability to enhance Pb extraction from contaminated soil driven by interfacial solar evaporation.The SA loaded sponge had a Pb adsorption capacity of 107.4 mg g^(-1).Coating the top surface of the SA sponge with rGO increased water evaporation performance to 1.81 kg m^(-2)h^(-1)in soil media under one sun illumination and with a wind velocity of 2 m s^(-1).Over 12 continuous days of indoor evaporation testing,the Pb extraction efficiency was increased by 22.0%under 1 sun illumination relative to that observed without illumination.Subsequently,Pb extraction was further improved by 48.9%under outdoor evaporation conditions compared to indoor conditions.Overall,this initial work shows the significant potential of interfacial solar evaporation technologies for Pb contaminated soil remediation,which should also be applicable to a variety of other environmental contaminants.
基金supported by the National Natural Science Foundation of China, No. 31671248the Natural Science Foundation of Beijing, No. 7222198 (both to NH)
文摘We previously combined reduced graphene oxide(rGO)with gelatin-methacryloyl(GelMA)and polycaprolactone(PCL)to create an rGO-GelMA-PCL nerve conduit and found that the conductivity and biocompatibility were improved.However,the rGO-GelMA-PCL nerve conduits differed greatly from autologous nerve transplants in their ability to promote the regeneration of injured peripheral nerves and axonal sprouting.Extracellular vesicles derived from bone marrow mesenchymal stem cells(BMSCs)can be loaded into rGO-GelMA-PCL nerve conduits for repair of rat sciatic nerve injury because they can promote angiogenesis at the injured site.In this study,12 weeks after surgery,sciatic nerve function was measured by electrophysiology and sciatic nerve function index,and myelin sheath and axon regeneration were observed by electron microscopy,immunohistochemistry,and immunofluorescence.The regeneration of microvessel was observed by immunofluorescence.Our results showed that rGO-GelMA-PCL nerve conduits loaded with BMSC-derived extracellular vesicles were superior to rGO-GelMA-PCL conduits alone in their ability to increase the number of newly formed vessels and axonal sprouts at the injury site as well as the recovery of neurological function.These findings indicate that rGO-GelMA-PCL nerve conduits loaded with BMSC-derived extracellular vesicles can promote peripheral nerve regeneration and neurological function recovery,and provide a new direction for the curation of peripheral nerve defect in the clinic.
基金Ho Chi Minh City University of Technology (HCMUT),VNU-HCM for supporting this study。
文摘In this study,three-dimensional porous magnesium ferrite/titanium dioxide/reduced graphene oxide(Mg Fe_2O_(4)-GM/TiO_(2)/rGO(MGTG))was successfully synthesized via green and hydrothermal-supported co-precipitation methods using the extract of Garcinia mangostana(G.mangostana)as a reducing agent.The characterization results indicate the successful formation of the nano/micro Mg Fe_(2)O_(4)(MFO)and TiO_(2) on the structure of the reduced graphene oxide(rGO),which can also act as efficient support,alleviating the agglomeration of the nano/micro MFO and TiO_(2).The synergic effects of the adsorption and photodegradation activity of the material were investigated according to the removal of crystal violet(CV)under ultraviolet light.The effects of catalyst dosage,CV concentration,and p H on the CV removal efficiency of the MGTG were also investigated.According to the results,the CV photodegradation of the MGTG-200 corresponded to the pseudo-first-order kinetic model.The reusability of the material after 10 cycles also showed a removal efficiency of 92%.This happened because the materials can easily be recollected using external magnets.In addition,according to the effects of different free radicals·O_(2)^(-),h^(+),and·OH on the photodegradation process,the photocatalysis mechanism of the MGTG was also thoroughly suggested.The antibacterial efficiency of the MGTG was also evaluated according to the inhibition of the Gram-positive bacteria strain Staphylococcus aureus(S.aureus).Concurrently,the antibacterial mechanism of the fabricated material was also proposed.These results confirm that the prepared material can be potentially employed in a wide range of applications,including wastewater treatment and antibacterial activity.
基金supported by the National Key Research and Development Project (Grant No. 2018YFE0124800)the National Key Research Program of China (Grant No.2022YFA1503100)+7 种基金Science and Technology Project of Jiangsu Province (Grant No. BZ2020011)National Natural Science Foundation of China (Grants No. 22173067)the Science and Technology Development FundMacao SAR(FDCT No. 0052/2021/A)Collaborative Innovation Center of Suzhou Nano Science&Technologythe Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)the 111 ProjectJoint International Research Laboratory of Carbon-Based Functional Materials and Devices
文摘Lithium-sulfur(Li-S) batteries can provide far higher energy density than currently commercialized lithium ion batteries, but challenges remain before it they are used in practice.One of the challenges is the shuttle effect that originates from soluble intermediates, like lithium polysulfides. To address this issue, we report a novel laminar composite, N,O-carboxymethyl chitosan-reduced graphene oxide(CC-rGO), which is manufactured via the self-assembly of CC onto GO and subsequent reduction of GO under an extreme condition of 1 Pa and-50°C. The synthesized laminar CC-rGO composite is mixed with acetylene black(AB) and coated on a commercial polypropylene(PP) membrane, resulting in a separator(CC-rGO/AB/PP) that can not only completely suppress the polysulfides penetration, but also can accelerate the lithium ion transportation, providing a Li-S battery with excellent cyclic stability and rate capability. As confirmed by theoretic simulations, this unique feature of CC-rGO is attributed to its strong repulsive interaction to polysulfide anions and its benefit for fast lithium ion transportation through the paths paved by the heteroatoms in CC.
基金funded by the Zhengzhou Materials Genome Institute,the National Talents Program of China,and Key Innovation Projects of the Zhengzhou Municipal City of China.
文摘The main bottleneck against industrial utilization of sodium ion batteries(SIBs)is the lack of high-capacity electrodes to rival those of the benchmark lithium ion batteries(LIBs).Here in this work,we have developed an economical method for in situ fabrication of nanocomposites made of crystalline few-layer graphene sheets loaded with ultrafine SnO_(2)nanocrystals,using short exposure of microwave to xerogel of graphene oxide(GO)and tin tetrachloride containing minute catalyzing dispersoids of chemically reduced GO(RGO).The resultant nanocomposites(SnO_(2)@MWG)enabled significantly quickened redox processes as SIB anode,which led to remarkable full anode-specific capacity reaching 538 mAh g^(−1)at 0.05 A g^(−1)(about 1.45 times of the theoretical capacity of graphite for the LIB),in addition to outstanding rate performance over prolonged charge–discharge cycling.Anodes based on the optimized SnO_(2)@MWG delivered stable performance over 2000 cycles even at a high current density of 5 A g^(−1),and capacity retention of over 70.4%was maintained at a high areal loading of 3.4 mg cm^(−2),highly desirable for high energy density SIBs to rival the current benchmark LIBs.
基金the Foundation of National Natural Science Foundation of China(51773169 and 51973173)the Natural Science Basic Research Plan for Distinguished Young Scholars in Shaanxi Province of China(2019JC-11)+2 种基金the Natural Science Basic Research Plan in Shaanxi Province of China(2020JQ-164)Y.Q.Guo thanks the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(CX202055)Polymer Electromagnetic Functional Materials Innovation Team of Shaanxi Sanqin Scholars.
文摘In order to ensure the operational reliability and infor-mation security of sophisticated electronic components and to protect human health,efficient electromagnetic interference(EMI)shielding materials are required to attenuate electromagnetic wave energy.In this work,the cellulose solution is obtained by dissolving cotton through hydrogen bond driving self-assembly using sodium hydroxide(NaOH)/urea solution,and cellulose aerogels(CA)are prepared by gelation and freeze-drying.Then,the cellulose carbon aerogel@reduced graphene oxide aerogels(CCA@rGO)are prepared by vacuum impregnation,freeze-drying followed by thermal annealing,and finally,the CCA@rGO/polydimethylsiloxane(PDMS)EMI shielding composites are prepared by backfilling with PDMS.Owing to skin-core structure of CCA@rGO,the complete three-dimensional(3D)double-layer con-ductive network can be successfully constructed.When the loading of CCA@rGO is 3.05 wt%,CCA@rGO/PDMS EMI shielding composites have an excellent EMI shielding effectiveness(EMI SE)of 51 dB,which is 3.9 times higher than that of the co-blended CCA/rGO/PDMS EMI shielding composites(13 dB)with the same loading of fillers.At this time,the CCA@rGO/PDMS EMI shielding composites have excellent thermal stability(T_(HRI) of 178.3℃)and good thermal conductivity coefficient(λ of 0.65 W m^(-1) K^(-1)).Excellent comprehensive performance makes CCA@rGO/PDMS EMI shielding composites great prospect for applications in lightweight,flexible EMI shielding composites.
基金financially supported by the National Natural Science Foundation of China (Nos. 51272110, 51772160, and 51771123)the Shenzhen Peacock Innovation Project (No. KQJSCX20170327151307811)+1 种基金the support of China Scholarship Council (No. 201506100018)the START project of Japan Science and Technology Agency (JST)
文摘Two-dimensional(2D)nanomaterials are categorized as a new class of microwave absorption(MA)materials owing to their high specific surface area and peculiar electronic properties.In this study,2D WS2-reduced graphene oxide(WS2-rGO)heterostructure nanosheets were synthesized via a facile hydrothermal process;moreover,their dielectric and MA properties were reported for the first time.Remarkably,the maximum reflection loss(RL)of the sample-wax composites containing 40 wt% WS2-rGO was-41.5 dB at a thickness of 2.7 mm;furthermore,the bandwidth where RL<-10 dB can reach up to 13.62 GHz(4.38-18 GHz).Synergistic mechanisms derived from the interfacial dielectric coupling and multiple-interface scattering after hybridization of WS2 with rGO were discussed to explain the drastically enhanced microwave absorption performance.The results indicate these lightweight WS2-rGO nanosheets to be potential materials for practical electromagnetic wave-absorbing applications.
基金supported by National Natural Science Foundation of China(21376105 and 21576113)Foshan Innovative and Entepreneurial Research Team Program(No.2014IT100062)
文摘A flexible asymmetric supercapacitor(ASC)based on a Co Al-layered double hydroxide(Co Al-LDH)electrode and a reduced graphene oxide(r GO) electrode was successfully fabricated. The Co Al-LDH electrode as a positive electrode was synthesized by directly growing Co Al-LDH nanosheet arrays on a carbon cloth(CC)through a facile hydrothermal method, and it delivered a specific capacitance of 616.9 F g^(-1)at a current density of1 A g^(-1). The r GO electrode as a negative electrode was synthesized by coating r GO on the CC via a simple dipcoating method and revealed a specific capacitance of110.0 F g^(-1)at a current density of 2 A g^(-1). Ultimately,the advanced ASC offered a broad voltage window(1.7 V)and exhibited a high superficial capacitance of1.77 F cm^(-2)at 2 m A cm^(-2)and a high energy density of0.71 m Wh cm^(-2)at a power density of 17.05 m W cm^(-2),along with an excellent cycle stability(92.9% capacitance retention over 8000 charge–discharge cycles).
基金supported by the Special Fund for the Development of Strategic Emerging Industries of Shenzhen City of China(No.JCYJ20140419141154246)the National Nature Science Foundation of China(No.11174227)Chinese Universities Scientific Fund
文摘A kind of sandwich-like NiCo_2O_4/rGO/NiO heterostructure composite has been successfully anchored on nickel foam substrate via a three-step hydrothermal method with successive annealing treatment. The smart combination of NiCo_2O_4, reduced graphene oxide(rGO), and NiO nanostructure in the sandwich-like nano architecture shows a promising synergistic effect for supercapacitors with greatly enhanced electrochemical performance. For serving as supercapacitor electrode, the NiCo_2O_4/rGO/NiO heterostructure materials exhibit remarkable specific capacitance of 2644 mF cm^(-2)at current density of 1 mA cm^(-2),and excellent capacitance retentions of 97.5% after 3000 cycles. It is expected that the present heterostructure will be a promising electrode material for high-performance supercapacitors.
基金supported by the Specialized Research Fund for the Doctoral Program of Higher Education(200800191013)the Fundamental Research Funds for the Central Universities
文摘Objective This study was aimed to investigate the toxic effects of 3 nanomaterials, i.e. multi-walled carbon nanotubes (MWCNTs), graphene oxide (GO), and reduced graphene oxide (RGO), on zebrafish embryos. Methods The 2-h post-fertilization (hpf) zebrafish embryos were exposed to MWCNTs, GO, and RGO at different concentrations (1, 5, 10, 50, 100 mg/L) for 96 h. Afterwards, the effects of the 3 nanomateria on spontaneous movement, heart rate, hatching rate, length of larvae, mortality, and malformations Is were evaluated. Results Statistical analysis indicated that RGO significantly inhibited the hatching of zebrafish embryos. Furthermore, RGO and MWCNTs decreased the length of the hatched larvae at 96 hpf. No obvious morphological malformation or mortality was observed in the zebrafish embryos after exposure to the three nanomaterials. Conclusion MWCNTs, GO, and RGO were all toxic to zebrafish embryos to influence embryos hatching and larvae length. Although no obvious morphological malformation and mortality were observed in exposed zebrafish embryos, further studies on the toxicity of the three nanomaterials are still needed.
基金financial support from the National Natural Science Foundation of China(grant no.21406052the Program for the Outstanding Young Talents of Hebei Province(grant no.BJ2014010)the Scientific Research Foundation for Selected Overseas Chinese Scholars,Ministry of Human Resources and Social Security of China(grant no.CG2015003002)
文摘The high-energy lithium/sulfur(Li/S) battery has become a very popular topic of research in recent years due to its high theoretical capacity of 1672 m Ah/g. However, the polysulfide shuttle effect remains of great concern with a great number of publications dedicated to its mitigation. In this contribution, a three-dimensional(3D) reduced graphene oxide/activated carbon(RGO/AC) film, synthesized by a simple hydrothermal method and convenient mechanical pressing, is sandwiched between the separator and the sulfur-based cathode, acting as a functional interlayer to capture and trap polysulfide species. Consequently, the Li/S cell with this interlayer shows an impressive initial discharge capacity of 1078 m Ah/g and a reversible capacity of 655 m Ah/g even after 100 cycles. The RGO/AC interlayer impedes the movement of polysulfide while providing unimpeded channels for lithium ion mass transfer. Therefore, the RGO/AC interlayer with a well-designed structure represents strong potential for high-performance Li/S batteries.
基金Financial support from National Nature Science Foundation of China(51971111)the Foundation of Graduate Innovation Center in NUAA(kfjj20200602)is gratefully acknowledgedOpen access funding provided by Shanghai Jiao Tong University
文摘Silver nanowire(Ag NW)has been considered as the promising building block for the fabrication of transparent electromagnetic interference(EMI)shielding films.However,the practical application of Ag NW-based EMI shielding films has been restricted due to the unsatisfactory stability of Ag NW.Herein,we proposed a reduced graphene oxide(rGO)decorated Ag NW film,which realizes a seamless integration of optical transparency,highly efficient EMI shielding,reliable durability and stability.The Ag NW constructs a highly transparent and conductive network,and the rGO provides additional conductive path,showing a superior EMI shielding effectiveness(SE)of 33.62 dB at transmittance of 81.9%.In addition,the top rGO layer enables the hybrid film with reliable durability and chemical stability,which can maintain 96%and 90%EMI SE after 1000 times bending cycles at radius of 2 mm and exposure in air for 80 days.Furthermore,the rGO/Ag NW films also possess fast thermal response and heating stability,making them highly applicable in wearable devices.The synergy of Ag NW and rGO grants the hybrid EMI shielding film multiple desired functions and meanwhile overcomes the shortcomings of Ag NW.This work provides a reference for preparing multifunctional integrated transparent EMI shielding film.
基金supported by the National Natural Science Foundation of China(Grant no.51672075,21271069,51772092,51704106)Science and Technology Program of Hunan Province(Grant no.2015JC3049)
文摘A new Fe3C-N-doped reduced graphene oxide(Fe3C-N-rGO)prepared by a facile method is used as a separator for high performance lithium-sulfur(Li-S)batteries.The Fe3C-N-rGO is coated on the surface of commercial polypropylene separator(Celgard 2400)close to the sulfur cathode.The special nanotubes are in-situ catalyzed by Fe3C nanoparticles.They could entrap lithium polysulfides(Li PSs)to restrain the shuttle effect and reduce the loss of active material.The battery with the modified separator and sulfur cathode shows an excellent cycle performance.It has a high rate performance,580.5 mAh/g at the high current rate of 4 C relative to 1075 mAh/g at 0.1 C.It also has an initial discharge capacity of 774.8 m Ah/g measured at 0.5 C and remains 721.8 mAh/g after 100 cycles with a high capacity retention of 93.2%.The outstanding performances are notable in recently reports with modified separator.