Co-reporter:Yi Fu Huang, Wen Hong RuanDong Ling Lin, Ming Qiu Zhang
ACS Applied Materials & Interfaces 2017 Volume 9(Issue 1) pp:
Publication Date(Web):December 16, 2016
DOI:10.1021/acsami.6b13145
Substituting conventional electrolyte for redox electrolyte has provided a new intriguing method for extending battery life. The efficiency of utilizing the contained redox species (RS) in the redox electrolyte can benefit from increasing the specific surface area of battery electrodes from the electrode side of the electrode–electrolyte interface, but is not limited to that. Herein, a new strategy using nanocomposite electrolyte is proposed to enlarge the interface with the aid of nanoinclusions from the electrolyte side. To do this, graphene oxide (GO) sheets are first dispersed in the electrolyte solution of tungstosilicic salt/lithium sulfate/poly(vinyl alcohol) (SiWLi/Li2SO4/PVA), and then the sheets are bridged to electrode, after casting and evaporating the solution on the electrode surface. By applying in situ conductive atomic force microscopy and Raman spectra, it is confirmed that the GO sheets doped with RS of SiWLi/Li2SO4 can be bridged and electrically reduced as an extended electrode–electrolyte interface. As a result, the RS-coated GO sheets bridged to LiTi2(PO4)3//LiMn2O4 battery electrodes are found to deliver extra energy capacity (∼30 mAh/g) with excellent electrochemical cycling stability, which successfully extends the battery life by over 50%.Keywords: battery life; bridging; graphene oxide; nanocomposite electrolyte; redox species;
Co-reporter:Gao-Ming Hou;Yi-Fu Huang;Wen-Hong Ruan
Journal of Solid State Electrochemistry 2016 Volume 20( Issue 7) pp:1903-1911
Publication Date(Web):2016 July
DOI:10.1007/s10008-015-3031-4
In the developing of wearable electronics and smart textiles, thin, lightweight, and flexible energy storage supercapacitor with high energy density has attracted the attention of many researchers in recent years. In this work, we prepared gel nano-composite electrolyte with the hypergrafted poly (amine-ester) nano-silica (HBPAE-SiO2) as inclusion. The electrochemical properties of the supercapacitor with the alkaline polymer electrolyte were evaluated by cyclic voltammetry, galvanostatic charge–discharge behavior, and electrochemical impedance spectroscopy. It was found that the incorporated HBPAE-SiO2 can greatly increase the specific capacitance of the supercapacitor, which was due to the enhanced ionic conductivity of gel electrolyte as well as good electrode–electrolyte contact. It is pointed out that the electroactivity of the inclusion may be also one reason. The best specific capacitance with 30 wt% HBPAE-SiO2 reached 160 F g−1, which was increased by 36.5 % compared with that of polyvinyl alcohol (PVA)-KOH system. Moreover, the capacity retention of solid-state supercapacitor can be 88 % after 10,000 cycles. The hypergrafted nano-silica modified polymer gel electrolyte is promising for the application of solid-state supercapacitor.
Co-reporter:Xianlei Hu;Gaoming Hou;Mingqiu Zhang
Journal of Solid State Electrochemistry 2016 Volume 20( Issue 7) pp:1845-1854
Publication Date(Web):2016 July
DOI:10.1007/s10008-015-3073-7
A new solid-state polymer composite electrolyte based on hypergrafted nano-silica (SiO2-g-HBPAE)/hyperbranched poly (amine-ester) (HBPAE) doped with lithium perchlorate (LiClO4) was studied in this paper. The N,N-diethylol-3-amine-2-methyl methylpropionate monomer was firstly synthesized by methyl methacrylate (MMA) and diethanolamine through Michael addition reaction and then self-condensed on the surface of nano-silica pretreated by 3-aminopropyltriethoxysilane (APTES) and MMA. The synthetic procedure of the monomers and SiO2-g-HBPAE/HBPAE was traced by fluorescence spectra. The size and grafting ratio of SiO2-g-HBPAE were characterized by transmission electron microscopy, static light scattering and thermogravimetric analysis. Incorporating SiO2-g-HBPAE to HBPAE could not only decrease the glass transition temperature of polymer according to the differential scanning calorimetry characterization, but also increase the elastic and viscosity modules indicated by rheological measurement results. Electrochemical properties of SiO2-g-HBPAE/HBPAE/LiClO4 were also investigated. The conductivity of SiO2-g-HBPAE/HBPAE with 50 wt% LiClO4 reached 1.4 × 10−5 S/cm at 30 °C and 10−3 S/cm at 100 °C. The lithium-ion transference number of synthesized hyperbranched electrolyte can be up to 0.55.
Co-reporter:Guomin Xu, Shuhao Qin, Jie Yu, Yifu Huang, Mingqiu Zhang and Wenhong Ruan
RSC Advances 2015 vol. 5(Issue 38) pp:29924-29930
Publication Date(Web):19 Mar 2015
DOI:10.1039/C5RA01401H
To study the effect of migration and selective localization of layered nanoparticles during melt compounding on the phase morphology of polymer blends, poly (ethylene terephthalate) (PET)/polyamide 6 (PA6)/organic montmorillonite (OMMT) ternary nanocomposites were prepared. Three different blending sequences were adopted either by pre-compounding OMMT into PET or into PA6 or by mixing all three components together. The morphology and tensile properties of PET/PA6/OMMT nanocomposites were investigated. TEM observation showed that OMMT platelets exclusively localized within the PA6 phase independent of the blending sequences, suggesting OMMT platelets migrated from PET into the PA6 phase during both the one-step and two-step compounding processes with pre-mixed PET/OMMT, and this migration was attributed to interfacial effects. SEM results revealed that the migration and selective localization of OMMT platelets had great influence on the size of the dispersed phase due to the conjunct action of the migration cutting effect and viscosity effect. The morphology determines the final properties of the nanocomposites as indicated by tensile test. It is believed that this work provides a way to tune the morphology and performance of immiscible blends.
Co-reporter:Li Li;Mingqiu Zhang
Polymer Composites 2015 Volume 36( Issue 12) pp:2248-2254
Publication Date(Web):
DOI:10.1002/pc.23137
Poly(vinylidene fluoride) (PVDF) nanocomposites with different loading of carbon nanotubes (CNT) and carbon black (CB) were prepared by melt blending method. The conductivity and mechanical properties of the nanocomposites were investigated. The results showed that percolation threshold of CNT/CB/PVDF nanocomposites appeared at a lower concentration (1.25 vol% CNT) than that of CNT/PVDF (>2.08 vol% CNT). The tensile strength of CNT/CB/PVDF nanocomposites was also improved, with 32.1% increase compared to PVDF and 18.0% increase compared to CNT/PVDF at loading of 1.25 vol% CNT/0.96 vol% CB. To explore the synergistic effect of CNT and CB, nonisothermal crystallization and isothermal crystallization behaviors of PVDF and its nanocomposites were studied by differential scanning calorimetry, and the crystallization morphology of them was observed under the three dimensional digital microscope with the polarized model. The crystallization rate of PVDF was speeded up markedly because of heterogeneous nucleation effect of nanoparticles, and CNT and CB nanoparticles had a synergistic effect on nucleation. Polarized microscope observation confirmed that spherulite size of PVDF became smaller owing to the accelerating of crystallization, which influenced the distribution of nanoparticles. The dispersion of nanofillers in matrix was observed by scanning electron microscope. It was revealed that CB could make CNT disperse more evenly in the PVDF matrix. The synergies network of CNT and CB is suggested to build in matrix, which improved conductivity and mechanical properties of PVDF nanocomposites. POLYM. COMPOS., 36:2248–2254, 2015. © 2014 Society of Plastics Engineers
Co-reporter:Yifu Huang, Mingqiu Zhang and Wenhong Ruan
Journal of Materials Chemistry A 2014 vol. 2(Issue 27) pp:10508-10515
Publication Date(Web):09 May 2014
DOI:10.1039/C4TA01464B
In this study, high-water-content boron-cross-linked graphene oxide/polyvinyl alcohol (B-GO/PVA) hydrogels were prepared by a freeze/thaw method and immersion in boric acid solution for boron cross-linking. High-water-content B-GO/PVA hydrogels with a water/polymer mass ratio ranging from 19:1 to 49:1 (water content 95–98) could be obtained. It is found that a small addition of GO can lead to significant reinforcement of the tensile strength of B-GO/PVA hydrogels with an increase in elongation. Compared to B-PVA hydrogel, a 144% increase of fracture tensile strength is achieved when the content of GO is 0.1 wt% (∼0.609 MPa, water content ∼ 95%). Meanwhile, compression and shear strength (0.1 MPa and 0.201 MPa, water content ∼ 95%) of such hydrogels are increased by 26% and 35%, respectively. A method of acquiring high-water-content PVA hydrogels and the reinforcing mechanism of B-GO/PVA hydrogels are suggested. It is believed that such new high-water-content hydrogels are promising materials in the application of biomedical engineering and polymer electrolytes.
Co-reporter:Yi-Fu Huang, Peng-Fei Wu, Ming-Qiu Zhang, Wen-Hong Ruan, Emmanuel P. Giannelis
Electrochimica Acta 2014 Volume 132() pp:103-111
Publication Date(Web):20 June 2014
DOI:10.1016/j.electacta.2014.03.151
•Gel electrolyte is prepared and used in electric double layer capacitor.•Insertion of boron crosslinks into GO agglomerates opens channels for ion migration.•Solid supercapacitors show excellent specific capacitance and cycle stability.•Nanocomposite electrolyte shows better thermal stability and mechanical properties.A new family of boron cross-linked graphene oxide/polyvinyl alcohol (GO-B-PVA) nanocomposite gels is prepared by freeze-thaw/boron cross-linking method. Then the gel electrolytes saturated with KOH solution are assembled into electric double layer capacitors (EDLCs). Structure, thermal and mechanical properties of GO-B-PVA are explored. The electrochemical properties of EDLCs using GO-B-PVA/KOH are investigated, and compared with those using GO-PVA/KOH gel or KOH solution electrolyte. FTIR shows that boron cross-links are introduced into GO-PVA, while the boronic structure inserted into agglomerated GO sheets is demonstrated by DMA analysis. The synergy effect of the GO and the boron crosslinking benefits for ionic conductivity due to unblocking ion channels, and for improvement of thermal stability and mechanical properties of the electrolytes. Higher specific capacitance and better cycle stability of EDLCs are obtained by using the GO-B-PVA/KOH electrolyte, especially the one at higher GO content. The nanocomposite gel electrolytes with excellent electrochemical properties and solid-like character are candidates for the industrial application in high-performance flexible solid-state EDLCs.
Co-reporter:Li Li, Mingqiu Zhang, Minzhi Rong and Wenhong Ruan
RSC Advances 2014 vol. 4(Issue 8) pp:3938-3943
Publication Date(Web):02 Dec 2013
DOI:10.1039/C3RA45134H
Poly(vinylidene fluoride) (PVDF) has excellent pyro- and piezoelectric properties which are related to the β-crystal of PVDF. Most of the β-crystal of PVDF can be transformed from the α-crystal by mechanical stretching. The effects of stretching conditions on the transformation from α to β phase of PVDF were studied in this paper. In addition, changes of crystalline structure of PVDF during the stretching process were observed in situ under an optical tensile stress microscopy tester, and the samples after being stretched were investigated using a 3D digital microscope and an infrared microscope. The results show that stretching temperature (Ts) and drawing ratio (λ) are critical to the transformation from α-crystal to β-crystal of PVDF. The Ts around 100 °C and λ above 3 is recommended. The in situ observation indicates that the deformation of crystalline structure began from the middle of α-spherulite and extended to another spherulite, and caused the large-scale transformation. Scanning results of infrared microspectroscopic and 3D digital microscopy revealed that α phase of PVDF would change into β phase with the deformation of the spherulite, and the distribution of the different crystalline phase in PVDF after being stretched was also given. It is believed that this work is instructive and meaningful to studies on phase transformation and production of the piezoelectric film of PVDF.
Co-reporter:Xue-bo Shi;Chun-lei Wu;Min-zhi Rong;Tibor Czigany
Chinese Journal of Polymer Science 2013 Volume 31( Issue 3) pp:377-387
Publication Date(Web):2013 March
DOI:10.1007/s10118-013-1225-8
To improve creep resistance of directional polytetrafluoroethylene (PTFE) films, epoxy grafted nano-SiO2 is mixed with PTFE powder before sintering and calender rolling. The aligned macromolecular chains (especially those in amorphous region) of the composite films can be bundled up by the nanoparticles to share the applied stress together. In addition, incorporation of silica nanoparticles increases crystallinity of PTFE and favors microfibrillation of PTFE in the course of large deformation. As result, PTFE films exhibit lower creep strain and creep rate, and higher tensile strength and hardness. The work is believed to open an avenue for manufacturing high performance fluoropolymers by nano-inclusions.
Co-reporter:Ming Hui Wang, Wen Hong Ruan, Yi Fu Huang, Lin Ye, Min Zhi Rong and Ming Qiu Zhang
Journal of Materials Chemistry A 2012 vol. 22(Issue 11) pp:4592-4598
Publication Date(Web):30 Jan 2012
DOI:10.1039/C2JM16097H
With the addition of 1 wt% nanosilica, oriented polypropylene (PP) shows ultra-high tensile strength at break (≈ 320 MPa, stronger than unidirectional glass fiber (∼60 wt%)/PP composites and a low-carbon steel) through solid-state drawing strategy. When nano-SiO2 is present in the drawn PP, the aligned macromolecular chains in amorphous regions can be tied by the well distributed nanofillers to share the stress together. Above the critical content of nanoparticles or drawing ratio, the nanoparticles form a percolated network throughout the matrix, facilitating stress transfer in the amorphous phases during tensile test. Additionally, the nanoparticles favor microfibrillation of the polymer matrix mainly constituted by the crystalline phases. As a result, the high strength covalent bonds of macromolecules in both the amorphous and crystalline phases are brought into full play. Although successful application of adding nanofillers to strengthen polymers is widely spread in rubbers and gels, the increase in strength of semi-crystalline polymers by low aspect ratio nano-inclusion is insignificant up to now. The work is believed to open an avenue for reinforcing semi-crystalline polymers by nanoparticles.
Co-reporter:Xian-Lei Hu, Gao-Ming Hou, Ming-Qiu Zhang, Min-Zhi Rong, Wen-Hong Ruan and Emmanuel P. Giannelis
Journal of Materials Chemistry A 2012 vol. 22(Issue 36) pp:18961-18967
Publication Date(Web):24 Jul 2012
DOI:10.1039/C2JM33156J
Solid-state nanocomposite polymer electrolytes based on poly(vinyl alcohol)(PVA) incorporating hyperbranched poly(amine-ester) (HBPAE) grafted nano-silica (denoted as SiO2-g-HBPAE) have been prepared and investigated. Through surface pretreatment of nanoparticles, followed by Michael-addition and a self-condensation process, hyperbranched poly(amine-ester) was directly polymerized from the surface of nano-silica. Then the hypergrafted nanoparticles were added to PVA matrix, and blended with lithium perchlorate via mold casting method to fabricate nanocomposite polymer electrolytes. By introducing hypergrafted nanoparticles, ionic conductivity of solid composite is improved significantly at the testing temperature. Hypergrafted nano-silica may act as solid plasticizer, promoting lithium salt dissociation in the matrix as well as improving segmental motion of matrix. In addition, tensile testing shows that such materials are soft and tough even at room temperature. From the dielectric spectra of nanocomposite polymer electrolyte as the function of temperature, it can be deduced that Arrhenius behavior appears depending on the content of hypergrafted nano-silica and concentration of lithium perchlorate. At a loading of 15 wt% hypergrafted nano-silica and 54 wt% lithium perchlorate, promising ionic conductivities of PVA nanocomposite polymer electrolyte are achieved, about 1.51 × 10−4 S cm−1 at 25 °C and 1.36 × 10−3 S cm−1 at 100 °C.
Co-reporter:Xianlei Hu, Mingqiu Zhang, Wenhong Ruan, Fang Zhu, Gangfeng Ouyang
Analytica Chimica Acta 2012 Volume 736() pp:62-68
Publication Date(Web):29 July 2012
DOI:10.1016/j.aca.2012.05.036
A novel solid-phase microextraction (SPME) fiber coating was prepared with siloxane-modified polyurethane acrylic resin by photo-cured technology. The ratio of two monomers was investigated to obtain good microphase separation structure and better extraction performance. The self-made fiber was then applied to organophosphorus pesticides (OPPs) analysis and several factors, such as extraction/desorption time, extraction temperature, salinity, and pH, were studied. The optimized conditions were: 15 min extraction at 25 °C, 5% Na2SO4 content, pH 7.0 and 4 min desorption in GC inlet. The self-made fiber coating exhibited better extraction efficiency for OPPs, compared with three commercial fiber coatings. Under the optimized conditions, the detection limits of 11 OPPs were from 0.03 μg L−1 to 0.5 μg L−1. Good recoveries and repeatabilities were obtained when the method was used to determine OPPs in ecological textile.Graphical abstractHighlights► A PUSA/PETA SPME fiber coating was prepared by photo-cured technology. ► The ratio of two monomers was optimized for better extraction performance. ► The fiber showed very good performance for OPPs analysis in textiles.
Co-reporter:Tong Hui Zhou, Wen Hong Ruan, Yu Liang Mai, Min Zhi Rong, Ming Qiu Zhang
Composites Science and Technology 2008 Volume 68(Issue 14) pp:2858-2863
Publication Date(Web):November 2008
DOI:10.1016/j.compscitech.2007.10.002
To prepare polypropylene (PP) based nanocomposites with improved mechanical performance, an in-situ cross-linking route was adopted by adding reactive monomers and cross-linking agents into the system containing nano-silica during melt compounding. In the meantime, the reactive monomers were polymerized and grafted onto to the nanoparticles, and the grafted polymer chains were cross-linked forming a network of the tiny reinforcement dispersed in linear PP matrix. Since the nanoparticles were interconnected by the semi-interpenetrating polymer network (semi-IPN)-like structure, the filler/matrix interaction was substantially enhanced, and both strength and toughness of the PP nanocomposites were significantly increased.
Co-reporter:T. H. Zhou;M. Z. Rong;W. H. Ruan;M. Q. Zhang;Y. L. Mai
Advanced Materials 2007 Volume 19(Issue 18) pp:2667-2671
Publication Date(Web):22 AUG 2007
DOI:10.1002/adma.200602611
A strategy for improving mobility of non-layered nanoparticles in a polymer matrix is proposed by reducing the interparticulate attraction and enhancing filler/matrix interaction in the rubbery state of the matrix, which induces additional energy dissipation mechanisms and increases toughness of the composites.
Co-reporter:Tong Hui Zhou, Wen Hong Ruan, Jing Lei Yang, Min Zhi Rong, Ming Qiu Zhang, Zhong Zhang
Composites Science and Technology 2007 Volume 67(11–12) pp:2297-2302
Publication Date(Web):September 2007
DOI:10.1016/j.compscitech.2007.01.015
In the present work, a one-step approach was suggested for improving creep resistance of thermoplastic polymers using nanoparticles. That is, SiO2 nanoparticles were pretreated by silane coupling agent to introduce reactive CC double bonds onto their surfaces. Afterwards, in the melt mixing with matrix polypropylene (PP), butyl acrylate monomers reacted with the silane coupling agent on the nanoparticles and then crosslinked to interconnect the particles with each other, while the PP chains penetrated into the networks, forming semi-interpenetrating polymer network (semi-IPN) structure. Taking the advantage of the specific microstructure, the nanoparticles were well distributed in the matrix with enhanced interfacial interaction. As a result, mobility of the matrix molecules was restricted to certain extent, and creep resistance of the nanocomposites became much higher than those of untreated nano-SiO2/PP system and unfilled PP as well.
Co-reporter:Xian-Lei Hu, Gao-Ming Hou, Ming-Qiu Zhang, Min-Zhi Rong, Wen-Hong Ruan and Emmanuel P. Giannelis
Journal of Materials Chemistry A 2012 - vol. 22(Issue 36) pp:NaN18967-18967
Publication Date(Web):2012/07/24
DOI:10.1039/C2JM33156J
Solid-state nanocomposite polymer electrolytes based on poly(vinyl alcohol)(PVA) incorporating hyperbranched poly(amine-ester) (HBPAE) grafted nano-silica (denoted as SiO2-g-HBPAE) have been prepared and investigated. Through surface pretreatment of nanoparticles, followed by Michael-addition and a self-condensation process, hyperbranched poly(amine-ester) was directly polymerized from the surface of nano-silica. Then the hypergrafted nanoparticles were added to PVA matrix, and blended with lithium perchlorate via mold casting method to fabricate nanocomposite polymer electrolytes. By introducing hypergrafted nanoparticles, ionic conductivity of solid composite is improved significantly at the testing temperature. Hypergrafted nano-silica may act as solid plasticizer, promoting lithium salt dissociation in the matrix as well as improving segmental motion of matrix. In addition, tensile testing shows that such materials are soft and tough even at room temperature. From the dielectric spectra of nanocomposite polymer electrolyte as the function of temperature, it can be deduced that Arrhenius behavior appears depending on the content of hypergrafted nano-silica and concentration of lithium perchlorate. At a loading of 15 wt% hypergrafted nano-silica and 54 wt% lithium perchlorate, promising ionic conductivities of PVA nanocomposite polymer electrolyte are achieved, about 1.51 × 10−4 S cm−1 at 25 °C and 1.36 × 10−3 S cm−1 at 100 °C.
Co-reporter:Yifu Huang, Mingqiu Zhang and Wenhong Ruan
Journal of Materials Chemistry A 2014 - vol. 2(Issue 27) pp:NaN10515-10515
Publication Date(Web):2014/05/09
DOI:10.1039/C4TA01464B
In this study, high-water-content boron-cross-linked graphene oxide/polyvinyl alcohol (B-GO/PVA) hydrogels were prepared by a freeze/thaw method and immersion in boric acid solution for boron cross-linking. High-water-content B-GO/PVA hydrogels with a water/polymer mass ratio ranging from 19:1 to 49:1 (water content 95–98) could be obtained. It is found that a small addition of GO can lead to significant reinforcement of the tensile strength of B-GO/PVA hydrogels with an increase in elongation. Compared to B-PVA hydrogel, a 144% increase of fracture tensile strength is achieved when the content of GO is 0.1 wt% (∼0.609 MPa, water content ∼ 95%). Meanwhile, compression and shear strength (0.1 MPa and 0.201 MPa, water content ∼ 95%) of such hydrogels are increased by 26% and 35%, respectively. A method of acquiring high-water-content PVA hydrogels and the reinforcing mechanism of B-GO/PVA hydrogels are suggested. It is believed that such new high-water-content hydrogels are promising materials in the application of biomedical engineering and polymer electrolytes.
Co-reporter:Ming Hui Wang, Wen Hong Ruan, Yi Fu Huang, Lin Ye, Min Zhi Rong and Ming Qiu Zhang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 11) pp:NaN4598-4598
Publication Date(Web):2012/01/30
DOI:10.1039/C2JM16097H
With the addition of 1 wt% nanosilica, oriented polypropylene (PP) shows ultra-high tensile strength at break (≈ 320 MPa, stronger than unidirectional glass fiber (∼60 wt%)/PP composites and a low-carbon steel) through solid-state drawing strategy. When nano-SiO2 is present in the drawn PP, the aligned macromolecular chains in amorphous regions can be tied by the well distributed nanofillers to share the stress together. Above the critical content of nanoparticles or drawing ratio, the nanoparticles form a percolated network throughout the matrix, facilitating stress transfer in the amorphous phases during tensile test. Additionally, the nanoparticles favor microfibrillation of the polymer matrix mainly constituted by the crystalline phases. As a result, the high strength covalent bonds of macromolecules in both the amorphous and crystalline phases are brought into full play. Although successful application of adding nanofillers to strengthen polymers is widely spread in rubbers and gels, the increase in strength of semi-crystalline polymers by low aspect ratio nano-inclusion is insignificant up to now. The work is believed to open an avenue for reinforcing semi-crystalline polymers by nanoparticles.
