The rapid development of flexible electronic devices requires the design of flexible energy-storage devices. Lithium-sulfur(Li-S) batteries are attracting much interest due to their high energy density. Therefore, fle...The rapid development of flexible electronic devices requires the design of flexible energy-storage devices. Lithium-sulfur(Li-S) batteries are attracting much interest due to their high energy density. Therefore, flexible Li-S batteries with high areal capacity are desired. Herein, we fabricated freestanding reduced graphene oxide-sulfur(RGO@S) composite films with a cross-linked structure using a blade coating technique, followed by a subsequent chemical reduction. The porous cross-linked structure endows the composite films with excellent electrochemical performance. The batteries based on RGO@S composite films could exhibit a high discharge capacity of 1381 m Ah/g at 0.1 C and excellent cycle stability. Furthermore, the freestanding composite film possesses excellent conductivity and high mechanical strength. Therefore, they can be used as the cathodes of flexible Li-S batteries. As a proof of concept, soft-packaged Li-S batteries were assembled and remained stable electrochemical performance under different bending states.展开更多
Nanocellulose has served as an eye-catching nanomaterial for constructing advanced functional devices with renewability,light weight,flexibility,and environmental friendliness.In this study,Co_(3)O_(4)/graphene/cellul...Nanocellulose has served as an eye-catching nanomaterial for constructing advanced functional devices with renewability,light weight,flexibility,and environmental friendliness.In this study,Co_(3)O_(4)/graphene/cellulose nanofiber(CNF)flexible composite films,in which the CNF acted as a spacer for the graphene,were prepared via a facile and scalable vacuum filtration method.The effects of the CNF on the microstructure,hydrophilicity,thermal stability,tensile strength,surface resistance,and electrochemical performance of the Co_(3)O_(4)/graphene/CNF composite films were systematically investigated.The results showed that the synergistic interaction of the CNF and graphene substantially improved the overall properties of the Co_(3)O_(4)/graphene/CNF composite films,particularly their hydrophilicity and tensile strength.Meanwhile,Co_(3)O_(4)/graphene/CNF composite films with a CNF content of 4%appeared to have the optimal electrochemical performance,with an area specific capacitance of 56 mF/cm^(2) and prominent capacitance retention of 95.6%at a current density of 1 A/g after 1000 cycles.This work demonstrated that the prepared Co_(3)O_(4)/graphene/CNF flexible composite films have great application potential in the field of flexible energy storage devices.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
Scientific research on deep in situ resources is highly important to the theory and technology system construction for deep in-situ resource exploitation.To obtain high-condition preserved core samples,it is vital to ...Scientific research on deep in situ resources is highly important to the theory and technology system construction for deep in-situ resource exploitation.To obtain high-condition preserved core samples,it is vital to maintain the original material,humidity and luminous flux information inside the core.Therefore,this study proposes a research and development strategy for a high-toughness and highbarrier sealing film based on the molecular structure design and filler synergistic enhancement via a deep solid-state sealing film using in situ substance preservation(ISP),in situ moisture preservation(IMP)and in situ light preservation(ILP)coring principles.A graphene/epoxy composite sealing film with a high barrier,high strength and high toughness was developed.The oxygen permeability of the film was 0.23 cm^(3)/(m^(2)·d),the water vapor permeability was 1.26 g/(m^(2)·d),and the light transmittance was 0.The tensile strength reached 15.4 MPa,and the toughness was 5242.9 kJ/m^(3).The results from the film substance and moisture preservation performance verification experiments showed that the sealing film had an excellent sealing effect on small molecules,such as water,alkanes and even ions,which further verified that the sealing film greatly contributed to the maintenance and preservation of deep in-situ resource reserves and abundance.展开更多
Graphene(G) was dispersed into 0.5% chitosan(Chit) solution,then the composite films were coated on glassy carbon electrode(GCE),the electrochemical behavior of rutin on a Chit/G modified GCE was investigated an...Graphene(G) was dispersed into 0.5% chitosan(Chit) solution,then the composite films were coated on glassy carbon electrode(GCE),the electrochemical behavior of rutin on a Chit/G modified GCE was investigated and the electrochemical parameters of rutin were calculated.Rutin effectively accumulated on the Chit/G/GCE and caused a pair of redox peaks at around 408 mV and 482 mV(vs.SCE) in 0.1M phosphate buffer solution(pH 4.0).Under optimized conditions,the anodic peak current was linear to the rutin concentration in the range of 5×107-1.04×105M.The regression equation was:y 9.9219x-0.0025,r=0.9958.The proposed method was successfully used for the determination of rutin content in tablet samples with satisfactory results.展开更多
Viscous aqueous solutions of chitosan and polyvinyl alcohol (PVA) were blended to enhance miscibility and avoid polymer phase separation. The mixtures were drop-casted and air dried to yield composite film materials t...Viscous aqueous solutions of chitosan and polyvinyl alcohol (PVA) were blended to enhance miscibility and avoid polymer phase separation. The mixtures were drop-casted and air dried to yield composite film materials that were characterized by equilibrium water uptake, physical stability in aqueous solution, and thermal stability. Chitosan/PVA blends have greater thermal stability, unique morphology, and reduced solubility in acidic solution, thus extending the useful pH range for chitosan as a sorbent material. The uptake properties of the films was investigated using methylene blue (MB) and a p-nitrophenol (PNP) dyes, where it was found that each single component polymer has greater uptake toward MB than PNP. A direct relationship between film composition (chitosan:PVA) with solution pH and the uptake of MB was observed. The results are in agreement with electrostatic interactions and contributions due to the hydrophobic effect for such composite materials.展开更多
Organic compounds are widely used in both industry and daily life,and composite bilayer films with organic compound-triggered bending properties are promising for applications of transducers,soft robotics,and so on.He...Organic compounds are widely used in both industry and daily life,and composite bilayer films with organic compound-triggered bending properties are promising for applications of transducers,soft robotics,and so on.Here,a universal and straightforward strategy to generate composite bilayer films with organic compoundtriggered bending properties is demonstrated.The composite bilayer films with organic compound-triggered bending properties are designed with bilayer structures,in which one layer is a porous polymeric membrane with appropriate solubility parameter that matches the value of organic solvents in order to produce prominent affinity to the solvent molecules,and the other layer is reduced graphene oxide membrane stacked on the porous polymeric membrane as an inert layer for restraining the swelling of the polymeric membrane on one side.Guided by matching the solubility parameters between solvent and polymer,a significant bending curvature of 27.3 cm-1 is obtained in acetone vapor.The results in this study will provide valuable guidance for designing and developing functional composite materials with significant organic compound-triggered bending properties.展开更多
This research work aims to reduce the band gap of thin layers of titanium oxide by the incorporation of graphene oxide sheets. Thin layers of the TiO2-GO composites were prepared on a glass substrate by the spin-coati...This research work aims to reduce the band gap of thin layers of titanium oxide by the incorporation of graphene oxide sheets. Thin layers of the TiO2-GO composites were prepared on a glass substrate by the spin-coating technique from GO and an aqueous solution of TiO2. A significant decrease in optical band gap was observed at the TiO2-GO compound compared to that of pure TiO2. Samples as prepared were characterized using XRD, SEM and UV-visible spectra. XRD analysis revealed the amorphous nature of the deposited layers. Scanning electron microscope reveals the dispersion of graphene nanofiles among titanium oxide nanoparticles distributed at the surface with an almost uniform size distribution. The band gap has been calculated and is around 2 eV after incorporation of Graphene oxide. The chemical bond C-Ti between the titanium oxide and graphene sheets is at the origin of this reduction.展开更多
With the booming development of portable and wearable electronic devices, flexible energy storage devices have attracted great attention. Among various energy storage devices, aqueous zinc ion batteries(ZIBs) are one ...With the booming development of portable and wearable electronic devices, flexible energy storage devices have attracted great attention. Among various energy storage devices, aqueous zinc ion batteries(ZIBs) are one of the promising candidates due to their low cost, good safety, high energy and power densities. However, the conventional cathodes of aqueous ZIBs were often prepared by mixing active materials with binders and conductive additives and then coating them onto current collectors. The resultant cathodes often suffer from unsatisfied flexibility. Herein, we fabricated freestanding reduced graphene oxide/NaV_3O_8·1.5H_2O(RGO/NVO) composite films with interlinked multilayered architecture by a vacuum filtrating process. Such composite films exhibit excellent mechanical property and high electronic conductivity. Owing to unique architecture, they display a high capacity of 410 mA h g^(-1) and excellent cycling performance up to 2000 cycles with a high capacity retention of 94%. Moreover, RGO/NVO composite films can directly serve as the cathodes of flexible aqueous ZIBs. As a proof of concept,flexible ZIBs were assembled based on the composite films. Impressively, they exhibit stable performance at different bending states, demonstrating great potential application in flexible energy storage devices.展开更多
Nitrogen dioxide(NO_(2))is a representative toxicant in air pollution that mostly arises from the exhaust gas released by automobiles.It is related to various respiratory diseases such as pneumonia and sudden infant d...Nitrogen dioxide(NO_(2))is a representative toxicant in air pollution that mostly arises from the exhaust gas released by automobiles.It is related to various respiratory diseases such as pneumonia and sudden infant death syndrome.Additionally,because the toxicity of nitrogen dioxide is high in overpopulated areas(i.e.,a capital or metropolis),the development of simple,practical,and facile sensors is highly needed.This work presents a flexible and disposable paper-based NO_(2)sensor based on a reduced graphene oxide/chitosan(r GO/CS)composite.The synthesized r GO/CS composite can be easily flexed and deformed into various shapes,which are attributed to chitosan molecules that function as a dispersion and reduction agent and support material.In addition,this composite can be attached to paper owing to its adhesive property;hence it can be utilized in versatile applications in a disposable manner.By analyzing the conductive change of the r GO/CS composite when it reacts with NO_(2),we can detect nitrogen dioxide in a concentration range of 0–100 ppm with a detection limit of 1 ppm.Moreover,we performed NO_(2)detection in the exhaust gas released by automobiles using the r GO/CS composite for practical application.The results indicated that the r GO/CS composite has the potential to be used in feasible gas sensing as a facile and disposable sensor under various conditions.展开更多
基金supported by the National Natural Science Foundation of China(21573116 , 51822205 , 21875121 and 51602218)Ministry of Science and Technology of China(2017YFA0206701)+1 种基金Ministry of Education of China(B12015)the Young Thousand Talents Program
文摘The rapid development of flexible electronic devices requires the design of flexible energy-storage devices. Lithium-sulfur(Li-S) batteries are attracting much interest due to their high energy density. Therefore, flexible Li-S batteries with high areal capacity are desired. Herein, we fabricated freestanding reduced graphene oxide-sulfur(RGO@S) composite films with a cross-linked structure using a blade coating technique, followed by a subsequent chemical reduction. The porous cross-linked structure endows the composite films with excellent electrochemical performance. The batteries based on RGO@S composite films could exhibit a high discharge capacity of 1381 m Ah/g at 0.1 C and excellent cycle stability. Furthermore, the freestanding composite film possesses excellent conductivity and high mechanical strength. Therefore, they can be used as the cathodes of flexible Li-S batteries. As a proof of concept, soft-packaged Li-S batteries were assembled and remained stable electrochemical performance under different bending states.
基金This work was financially supported by the National Natural Science Foundation of China(grant no.22078306)Key Research and Development Program of Zhejiang Province(grant no.2020C02021)+1 种基金521 Talent Cultivation Program of Zhejiang Sci-Tech University(grant no.11110132521310)Qujiang Science and Technology Project(grant no.QJ2020023).
文摘Nanocellulose has served as an eye-catching nanomaterial for constructing advanced functional devices with renewability,light weight,flexibility,and environmental friendliness.In this study,Co_(3)O_(4)/graphene/cellulose nanofiber(CNF)flexible composite films,in which the CNF acted as a spacer for the graphene,were prepared via a facile and scalable vacuum filtration method.The effects of the CNF on the microstructure,hydrophilicity,thermal stability,tensile strength,surface resistance,and electrochemical performance of the Co_(3)O_(4)/graphene/CNF composite films were systematically investigated.The results showed that the synergistic interaction of the CNF and graphene substantially improved the overall properties of the Co_(3)O_(4)/graphene/CNF composite films,particularly their hydrophilicity and tensile strength.Meanwhile,Co_(3)O_(4)/graphene/CNF composite films with a CNF content of 4%appeared to have the optimal electrochemical performance,with an area specific capacitance of 56 mF/cm^(2) and prominent capacitance retention of 95.6%at a current density of 1 A/g after 1000 cycles.This work demonstrated that the prepared Co_(3)O_(4)/graphene/CNF flexible composite films have great application potential in the field of flexible energy storage devices.
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supported by the Program for National Natural Science Foundation of China(Nos.52004166,51827901 and U2013603)Guangdong Introducing Innovative and Enterpreneurial Teams(No.2019ZT08G315).
文摘Scientific research on deep in situ resources is highly important to the theory and technology system construction for deep in-situ resource exploitation.To obtain high-condition preserved core samples,it is vital to maintain the original material,humidity and luminous flux information inside the core.Therefore,this study proposes a research and development strategy for a high-toughness and highbarrier sealing film based on the molecular structure design and filler synergistic enhancement via a deep solid-state sealing film using in situ substance preservation(ISP),in situ moisture preservation(IMP)and in situ light preservation(ILP)coring principles.A graphene/epoxy composite sealing film with a high barrier,high strength and high toughness was developed.The oxygen permeability of the film was 0.23 cm^(3)/(m^(2)·d),the water vapor permeability was 1.26 g/(m^(2)·d),and the light transmittance was 0.The tensile strength reached 15.4 MPa,and the toughness was 5242.9 kJ/m^(3).The results from the film substance and moisture preservation performance verification experiments showed that the sealing film had an excellent sealing effect on small molecules,such as water,alkanes and even ions,which further verified that the sealing film greatly contributed to the maintenance and preservation of deep in-situ resource reserves and abundance.
基金support of the Twelfth Five-Year National Science and Technology Support Program (2011BAI05B02)supported by the Fundamental Research Funds for the Central Universities (lzujbky-2011-95)+1 种基金the Project of Science and Technology Agency of Lanzhou (No.2011-1-67)item of scientific and technological research from Gansu province administration bureau of traditional Chinese medicine (GZK-2011-73),Gansu,China
文摘Graphene(G) was dispersed into 0.5% chitosan(Chit) solution,then the composite films were coated on glassy carbon electrode(GCE),the electrochemical behavior of rutin on a Chit/G modified GCE was investigated and the electrochemical parameters of rutin were calculated.Rutin effectively accumulated on the Chit/G/GCE and caused a pair of redox peaks at around 408 mV and 482 mV(vs.SCE) in 0.1M phosphate buffer solution(pH 4.0).Under optimized conditions,the anodic peak current was linear to the rutin concentration in the range of 5×107-1.04×105M.The regression equation was:y 9.9219x-0.0025,r=0.9958.The proposed method was successfully used for the determination of rutin content in tablet samples with satisfactory results.
基金This work was supported by the National Natural Science Foundation of China(Grants No.20075006,29975006,20375012)the Foundation for Ph.D.Thesis Research(No.20010532008)the Foundation of Science Commission of Yunnan Province(No.2002B0033M).
文摘Viscous aqueous solutions of chitosan and polyvinyl alcohol (PVA) were blended to enhance miscibility and avoid polymer phase separation. The mixtures were drop-casted and air dried to yield composite film materials that were characterized by equilibrium water uptake, physical stability in aqueous solution, and thermal stability. Chitosan/PVA blends have greater thermal stability, unique morphology, and reduced solubility in acidic solution, thus extending the useful pH range for chitosan as a sorbent material. The uptake properties of the films was investigated using methylene blue (MB) and a p-nitrophenol (PNP) dyes, where it was found that each single component polymer has greater uptake toward MB than PNP. A direct relationship between film composition (chitosan:PVA) with solution pH and the uptake of MB was observed. The results are in agreement with electrostatic interactions and contributions due to the hydrophobic effect for such composite materials.
基金Supported by the National Natural Science Foundation of China(21490582,21622604)the Program for Changjiang Scholars and Innovative Research Team in University(IRT15R48)the State Key Laboratory of Polymer Materials Engineering(sklpme2017-3-03,sklpme2014-1-01).
文摘Organic compounds are widely used in both industry and daily life,and composite bilayer films with organic compound-triggered bending properties are promising for applications of transducers,soft robotics,and so on.Here,a universal and straightforward strategy to generate composite bilayer films with organic compoundtriggered bending properties is demonstrated.The composite bilayer films with organic compound-triggered bending properties are designed with bilayer structures,in which one layer is a porous polymeric membrane with appropriate solubility parameter that matches the value of organic solvents in order to produce prominent affinity to the solvent molecules,and the other layer is reduced graphene oxide membrane stacked on the porous polymeric membrane as an inert layer for restraining the swelling of the polymeric membrane on one side.Guided by matching the solubility parameters between solvent and polymer,a significant bending curvature of 27.3 cm-1 is obtained in acetone vapor.The results in this study will provide valuable guidance for designing and developing functional composite materials with significant organic compound-triggered bending properties.
文摘This research work aims to reduce the band gap of thin layers of titanium oxide by the incorporation of graphene oxide sheets. Thin layers of the TiO2-GO composites were prepared on a glass substrate by the spin-coating technique from GO and an aqueous solution of TiO2. A significant decrease in optical band gap was observed at the TiO2-GO compound compared to that of pure TiO2. Samples as prepared were characterized using XRD, SEM and UV-visible spectra. XRD analysis revealed the amorphous nature of the deposited layers. Scanning electron microscope reveals the dispersion of graphene nanofiles among titanium oxide nanoparticles distributed at the surface with an almost uniform size distribution. The band gap has been calculated and is around 2 eV after incorporation of Graphene oxide. The chemical bond C-Ti between the titanium oxide and graphene sheets is at the origin of this reduction.
基金supported by the National Natural Science Foundation of China(21573116,51822205,21875121,51602218)Ministry of Science and Technology of China(2017YFA0206701)+3 种基金Ministry of Education of China(B12015)Tianjin Basic and High-Tech Development(16PTSYJC00030)the Fundamental Research Funds for the Central Universitiesthe Young Thousand Talents Program
文摘With the booming development of portable and wearable electronic devices, flexible energy storage devices have attracted great attention. Among various energy storage devices, aqueous zinc ion batteries(ZIBs) are one of the promising candidates due to their low cost, good safety, high energy and power densities. However, the conventional cathodes of aqueous ZIBs were often prepared by mixing active materials with binders and conductive additives and then coating them onto current collectors. The resultant cathodes often suffer from unsatisfied flexibility. Herein, we fabricated freestanding reduced graphene oxide/NaV_3O_8·1.5H_2O(RGO/NVO) composite films with interlinked multilayered architecture by a vacuum filtrating process. Such composite films exhibit excellent mechanical property and high electronic conductivity. Owing to unique architecture, they display a high capacity of 410 mA h g^(-1) and excellent cycling performance up to 2000 cycles with a high capacity retention of 94%. Moreover, RGO/NVO composite films can directly serve as the cathodes of flexible aqueous ZIBs. As a proof of concept,flexible ZIBs were assembled based on the composite films. Impressively, they exhibit stable performance at different bending states, demonstrating great potential application in flexible energy storage devices.
基金supported by the National Research Foundation of Korea(NRF)under Grant Nos.NRF-2017M3A9F1031229,NRF2017R1E1A1A01075439,and NRF-2019R1C1C1005668The Korea Environment Industry&Technology Institute(KEITI)through its Ecological Imitation-based Environmental Pollution Management Technology Development Project+1 种基金funded by the Korea Ministry of Environment(MOE)(2019002800009)And Korea University(Grant No.K2111511)。
文摘Nitrogen dioxide(NO_(2))is a representative toxicant in air pollution that mostly arises from the exhaust gas released by automobiles.It is related to various respiratory diseases such as pneumonia and sudden infant death syndrome.Additionally,because the toxicity of nitrogen dioxide is high in overpopulated areas(i.e.,a capital or metropolis),the development of simple,practical,and facile sensors is highly needed.This work presents a flexible and disposable paper-based NO_(2)sensor based on a reduced graphene oxide/chitosan(r GO/CS)composite.The synthesized r GO/CS composite can be easily flexed and deformed into various shapes,which are attributed to chitosan molecules that function as a dispersion and reduction agent and support material.In addition,this composite can be attached to paper owing to its adhesive property;hence it can be utilized in versatile applications in a disposable manner.By analyzing the conductive change of the r GO/CS composite when it reacts with NO_(2),we can detect nitrogen dioxide in a concentration range of 0–100 ppm with a detection limit of 1 ppm.Moreover,we performed NO_(2)detection in the exhaust gas released by automobiles using the r GO/CS composite for practical application.The results indicated that the r GO/CS composite has the potential to be used in feasible gas sensing as a facile and disposable sensor under various conditions.