Co-reporter:Chunli Zhou, Xiaohong Chen, Haiyan Liu, Jisheng Zhou, Zhaokun Ma, Mengqiu Jia, Huaihe Song
Electrochimica Acta 2017 Volume 236(Volume 236) pp:
Publication Date(Web):10 May 2017
DOI:10.1016/j.electacta.2017.03.107
•Heteroatom-doped multilocular carbon nanospheres (HMCSs) are synthesized for supercapacitors.•HMCSs-800 exhibits particular multilocular structure, high micropore content and proper heteroatom-doped content.•HMCSs-800 possesses high surface utilization (0.66 F m−2) and excellent rate capability (137 F g−1 at 20 A g−1).Heteroatom-doped multilocular carbon nanospheres (HMCSs) are synthesized by carbonizing multilocular polyaniline nanospheres (MPSs) which are prepared via metal-catalyzed polymerization in the presence of cupric nitrate as catalyst and ammonium persulfate as oxidant. The impacts of carbonization temperature on the morphology, structure and property of HMCSs are investigated. The results show that the carbonized sample at 800 °C (HMCSs-800) has a specific surface area of 283 m2 g−1, nitrogen content of 7.15% and oxygen content of 8.78%, and exhibits the specific capacitance of 186 F g−1 at the current density of 0.5 A g−1. Most importantly, HMCSs-800 possesses high surface utilization (0.66 F m−2) and excellent rate capability (73.8% retention at 20 A g−1 relative to the capacitance of 0.5 A g−1). These results are superior to that of other carbon materials in most reports. The specific capacitance still preserves 91.3% after 5000 charge/discharge cycles at the current density of 5 A g−1, demonstrating good cyclic stability. The outstanding electrochemical performance of HMCSs-800 can be ascribed to the providential integrate of particular multilocular structure, high micropore content and proper heteroatom content.Download high-res image (123KB)Download full-size image
Co-reporter:Yu Wang, Yuhong Jin, Rupeng Zhang, Mengqiu Jia
Applied Surface Science 2017 Volume 413(Volume 413) pp:
Publication Date(Web):15 August 2017
DOI:10.1016/j.apsusc.2017.03.241
•3D ZnFe2O4-graphene aerogel composites are obtained by a facile method.•The specific capacity of as-prepared 3D ZnFe2O4-graphene aerogel composites are 1049 mAh g−1 at 100 mA g−1 after 100 cycles.•Excellent rate capabilities are observed for 3D ZnFe2O4-graphene aerogel.•3D ZnFe2O4-graphene aerogel shows enhanced cyclic stability.ZnFe2O4-graphene aerogels (ZnFe2O4/GAs) composites are prepared by two-step method (hydrothermal-calcination). Highly-purified ZnFe2O4 nanoparticles are dispersed uniformly on three-dimensional (3D) GAs substrate. The mass loading of ZnFe2O4 in ZnFe2O4/GAs composites is 89.3%. Compared with pure ZnFe2O4 sample, the ZnFe2O4/GAs composites exhibit much higher irreversible capacity of 1449.4 mAh g−1 and enhanced cycling stability (1049 mAh g−1 at 100 mA g−1 after 100 cycles). The improved electrochemical performance of the ZnFe2O4/GAs composites could be attributed from the synergetic effect between 3D conductive GAs and nanostructured ZnFe2O4.
Co-reporter:Huan Liu, Mengqiu Jia, Qizhen Zhu, Bin Cao, Renjie Chen, Yu Wang, Feng Wu, and Bin Xu
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 40) pp:26878
Publication Date(Web):September 19, 2016
DOI:10.1021/acsami.6b09496
Transition metal oxides can be considered as appealing candidates for sodium ion battery anode materials because these low-cost materials possess high capacity and enhanced safety. However, the practical application of these materials is usually limited by their low electronic conductivity and serious volume change during the charging–discharging process. Herein, we report the fabrication of 3D-0D graphene-Fe3O4 quantum dot hybrids by a facile one-pot hydrothermal approach as anode materials for sodium-ion batteries. Fe3O4 quantum dots with an average size of 4.9 nm are anchored on the surface of 3D structured graphene nanosheets homogeneously. Such unique hierarchical structure are advantageous for enlarging the electrode/electrolyte interface area and enhancing the electrochemical activity of the hybrid materials, inhibiting particle aggregation of Fe3O4 and accommodating their volume change during the charging–discharging process as well as enabling fast diffusion of electrons and rapid transfer of electrolyte ions. Consequently, the 3D-0D graphene-Fe3O4 quantum dot hybrids exhibit ultrahigh sodium storage capacity (525 mAh g–1 at 30 mA g–1), outstanding cycling stability (312 mAh g–1 after 200 cycles at 50 mA g–1) and superior rate performance (56 mAh g–1 at 10 A g–1).Keywords: Fe3O4; graphene; quantum dots; sodium-ion batteries; three-dimensional structure
Co-reporter:Huan Liu, Mengqiu Jia, Bin Cao, Renjie Chen, Xinying Lv, Renjie Tang, Feng Wu, Bin Xu
Journal of Power Sources 2016 Volume 319() pp:195-201
Publication Date(Web):1 July 2016
DOI:10.1016/j.jpowsour.2016.04.040
•Nitrogen-doped carbon/graphene (NCG) hybrid materials were prepared for SIB.•The NCG has large interlayer distance with a nitrogen content of 7.54 at%.•Nitrogen-doped carbon sheets coated on both sides of graphene.•High reversible sodium storage capacity of 336 mAh g−1 at 30 mA g−1.•Good cycle durability and excellent rate capability (94 mAh g−1 at 5 A g−1).Nitrogen-doped carbon/graphene (NCG) hybrid materials were prepared by an in-situ polymerization and followed pyrolysis for sodium-ion batteries. The NCG has a large interlayer distance (0.360 nm) and a high nitrogen content of 7.54 at%, resulting in a high reversible sodium storage capacity of 336 mAh g−1 at 30 mA g−1. The NCG shows a sandwich-like structure, i.e. nitrogen-doped carbon nanosheets closely coated on both sides of graphene. The carbon nanosheets shorten the ion diffusion distance, while the sandwiched graphene with high electronic conductivity guarantees fast electron transport, making the NCG exhibit excellent rate capability (94 mAh g−1 at 5 A g−1). It also exhibits good cycle stability with a capacity retention of 89% after 200 cycles at 50 mA g−1.
Co-reporter:Huan Liu, Mengqiu Jia, Meng Wang, Renjie Chen, Ning Sun, Qizhen Zhu, Feng Wu and Bin Xu
RSC Advances 2016 vol. 6(Issue 82) pp:78235-78240
Publication Date(Web):12 Aug 2016
DOI:10.1039/C6RA17485J
The floral variant of mesoporous carbon was simply prepared by direct pyrolysis of zinc citrate followed by washing with dilute hydrochloric acid. The unique floral microstructure endows the carbon with ultrahigh reversible capacity, excellent cycle stability and superior rate performance as an anode material for both sodium ion batteries and lithium ion batteries. The floral variant of mesoporous carbon exhibits a reversible sodium storage capacity as high as 438.5 mA h g−1 at a current density of 30 mA g−1 and retains a value of 68.7 mA h g−1 at an enhanced current density of 10 A g−1. Moreover, the floral mesoporous carbon can deliver a tremendous reversible capacity up to 1370 mA h g−1 at 50 mA g−1 as an anode for lithium ion batteries. It can output a high reversible capacity of 222 mA h g−1 even when being charged and discharged at 50 A g−1. Based on the astounding capacity and rate performance, the floral variant of mesoporous carbon can be regarded as one of the most promising anode materials for both sodium-ion and lithium-ion batteries.
Co-reporter:Huan Liu, Bin Xu, Mengqiu Jia, Mei Zhang, Bin Cao, Xiaonan Zhao, Yu Wang
Applied Surface Science 2015 Volume 332() pp:40-46
Publication Date(Web):30 March 2015
DOI:10.1016/j.apsusc.2015.01.129
Highlights
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The composites of polyaniline nanofiber and large mesoporous carbon were prepared for supercapacitors.
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The large mesoporous carbons were simply prepared by nano-CaCO3 template method.
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The composites exhibit high capacitance and good rate capability and cycle stability.
Co-reporter:Dahai Gao, Mengqiu Jia
Applied Surface Science 2015 Volume 343() pp:172-180
Publication Date(Web):15 July 2015
DOI:10.1016/j.apsusc.2015.03.024
Highlights
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The hierarchical particles were prepared by a simple, mild hydrothermal process.
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The obtained “chestnut” ZnO particles show dual-scale morphology with high roughness.
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FEVE derivative was creatively imported to graft onto hierarchical particles.
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Superhydrophobic surfaces were obtained, on which the contact angles surpass 150°.
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A special model was proposed to explain the wetting state in this work.
Co-reporter:Dahai Gao, Mengqiu Jia
Applied Surface Science 2015 Volume 359() pp:89-97
Publication Date(Web):30 December 2015
DOI:10.1016/j.apsusc.2015.09.235
Highlights
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Hierarchical particles with high roughness were prepared by modified hydrothermal route.
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The high roughness is provided by extremely low thickness of sheet crystals.
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FEVE polymer derivative was used for surface treatment of hierarchical surface.
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The novel particles via surface treatment were firstly used as superhydrophobic materials.
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The product properties were compared with multi-scale ZnO particles via conventional route.
Co-reporter:Yuhong Jin, Mengqiu Jia
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2015 Volume 464() pp:17-25
Publication Date(Web):5 January 2015
DOI:10.1016/j.colsurfa.2014.09.032
•We prepared a new graphene-SnO2-polyaniline (GSP) composite via one-pot method.•SnO2 nanoparticles and polyaniline nanofibers are deposited on the graphene sheets.•A maximum capacitance of 913.4 F g−1 of GSP composite is achieved at 5 mV s−1.•The GSP composite shows the capacitance retention is 90.8% after 1000 cycles.In the presence of graphene oxide (GO) substrate, nanostructured graphene-SnO2-polyaniline (GSP) ternary composite is synthesized via one-pot method, including that GO is reduced by Sn2+ and tiny SnO2 nanoparticles are homogeneously distributed on the graphene sheets and following that polyaniline (PANI) is in situ synthesized on the surface of graphene-SnO2 (GS) composite in order to obtain GSP ternary composite. The electrochemical results demonstrate that GSP ternary composite achieves a maximum capacitance of 913.4 F g−1 at 5 mV s−1, retains 90.8% of the initial specific capacitance after 1000 cycles. The extraordinary electrochemical properties of the GSP ternary composite are attributed to good combination and the synergistic effect among the three components. Therefore, graphene based ternary composite can be a promising electrode material for supercapacitors.Novel graphene-SnO2-polyaniline ternary composite is facilely synthesized by one-pot method. The test results show that the as-prepared ternary composite has a high specific capacitance (913.4 F g−1 at 5 mV s−1) and long cycle life (over 1000 times).
Co-reporter:Yuhong Jin, Mou Fang, Mengqiu Jia
Applied Surface Science 2014 Volume 308() pp:333-340
Publication Date(Web):30 July 2014
DOI:10.1016/j.apsusc.2014.04.168
Highlights
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We develop a new and easy method to prepare graphene–polyaniline composite.
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The method includes reduction of graphene oxide by aniline followed by polymerization.
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Different characterizations confirm that GO can be reduced by aniline.
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Polyaniline nanofiber can be deposited on the surface of graphene.
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A high specific capacitance of 965 F g−1 is obtained at 0.5 A g−1.
Co-reporter:Qianlei Jiang, Daozhong Hu, Mengqiu Jia, Ruisheng Xue
Applied Surface Science 2014 Volume 321() pp:109-115
Publication Date(Web):1 December 2014
DOI:10.1016/j.apsusc.2014.09.080
Highlights
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SnSb deposits were directly electro-co-deposited on Cu substrates.
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We showed heat treatment effect on SnSb-based Cu electrode characteristics.
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The electrochemical properties depend strongly on heat-treated temperature.
Co-reporter:Yuhong Jin, Mengqiu Jia
Synthetic Metals 2014 Volume 189() pp:47-52
Publication Date(Web):March 2014
DOI:10.1016/j.synthmet.2013.12.016
•PANIFs are homogeneously dispersed on the graphene oxide nanosheets.•PANIF-GO composite shows only 9.4% specific capacitance loss after 2000 cycles.•PANIF-GO composite shows excellent electrochemical capacitive properties.•We report an easy method to prepare PANIF-GO composite by oil–water interfacial polymerization.•A high specific capacitance of 965 F g−1 is obtained at 0.5 A g−1.Polyaniline nanofiber-graphene oxide (PANIF-GO) hybrids were fabricated by oil–water interfacial polymerization. The structures of PANIF-GO hybrids, pure PANIF and GO were examined by high resolution transmission electron microscopy. It was found that PANIFs were homogeneously inserted between the GO layers or absorbed on the surface of the GO. Fourier transform infrared spectroscopy and X-ray diffraction showed that PANIFs effectively increased the interlayer distance of GO from 0.83 nm to 1.38 nm. Electrochemical properties for the hybrid electrode were tested by cyclic voltammetry and electrochemical impedance spectroscopy using a three-electrode system. The results indicated that a high specific capacitance of 564.7 F g−1 for the hybrids was measured at the current density of 0.5 A g−1 in a 1 M H2SO4 aqueous solution compared to 352.8 F g−1 for pure PANIF and 30.1 F g−1 for GO. Moreover, the PANIF-GO hybrids showed a very long cycle life with only 9.4% specific capacitance loss after 2000 cycles. The as-prepared hybrids are remarkable electrode materials for the supercapacitors.
Co-reporter:Moussa Tamboura;Anna M. Mikhailova;Meng Qiu Jia
Silicon 2014 Volume 6( Issue 1) pp:45-56
Publication Date(Web):2014 January
DOI:10.1007/s12633-013-9149-z
Using zinc phosphate, micaceous iron oxide and their combination in the composition of the undercoat, a series of novel multilayer paint systems based on different silicone-urethane binders with the same R/Si and Ph/R ratio have been formulated. The developed paint systems showed excellent mechanical, adhesion and chemical properties. Scanning Electron Microscopy (SEM) analysis of the surface of the paint systems shows no fractures or holes. The electrochemical impedance spectroscopy (EIS) evaluation of the developed paint systems confirms their excellent protective and anticorrosion properties, especially for Silicone-Urethane-Urea (SPUU) based paint systems with a combination of pigments in the composition of the undercoat. SPUU-based paint systems show low water uptake. The new multilayer silicone-urethane-based paint systems can be used as a anticorrosion primer.
Co-reporter:Mei Zhang, Xing Yang, Xinfeng Kan, Xin Wang, Li Ma, Mengqiu Jia
Electrochimica Acta 2013 Volume 112() pp:727-734
Publication Date(Web):1 December 2013
DOI:10.1016/j.electacta.2013.09.034
Carbon-encapsulated CoFe2O4/graphene (C@CFO/G) nanocomposite was prepared by a facile hydrothermal strategy and subsequently in situ pyrolysis process. The small-size CoFe2O4 nanoparticles encapsulated within thin carbon shells anchor onto G nanosheets with crumpled and waved structure for C@CFO/G nanocomposite. The as-synthesized nanocomposite delivers high reversible capacity of 925.6 mAh g−1 at 100 mA g−1 after 50 cycles. It exhibits rate capability of 772.3, 430.6 and 305.3 mA hg−1, even at 200, 800 and 1600 mA g−1, respectively, indicating outstanding rate capability and cycle stability. The improved electrochemical performance is ascribed to the well-designed structure with carbon shells and two dimension G nanosheets. The C@CFO/G nanocomposite will be an ideal candidate of anode material for lithium ion batteries.
Co-reporter:Shuo Huang, Yuhong Jin, Mengqiu Jia
Electrochimica Acta 2013 Volume 95() pp:139-145
Publication Date(Web):15 April 2013
DOI:10.1016/j.electacta.2013.01.045
In this study, graphene/Co3O4 composites are prepared through a simple process under mild hydrothermal conditions. Sodium carbonate (Na2CO3) can produce many OH− and CO32− ions after dissolution and hydrolysis in a water–isopropanol system, thereby making it applicable as both depositing agent and reducing agent in the synthesis of graphene/Co2(OH)2CO3 composites. Remarkably, the galvanosta charge–discharge test shows that the specific capacitance value of the as-obtained composites reaches a high value of 443 F g−1 at a high current density of 5 A g−1, which is significantly improved in relation to Co3O4, and the capacitance retains 54% of capacitance at 60 A g−1. The fact that the specific capacitance remains 97.1% after 1000 continuous charge–discharge cycles at 10 A g−1 indicates that the as-prepared material has an excellent cycle life. The effect of the feeding ratios between Co3O4 and graphite oxide on the electrochemical performance has also been studied.
Co-reporter:Bin Xu, Dongfang Zheng, Mengqiu Jia, Gaoping Cao, Yusheng Yang
Electrochimica Acta 2013 Volume 98() pp:176-182
Publication Date(Web):30 May 2013
DOI:10.1016/j.electacta.2013.03.053
•Carbons were simply prepared by pyrolysis of nitrogen-containing organic salt.•The carbons have developed porosity and rich nitrogen element.•The carbon exhibits high capacitance in aqueous supercapacitors.•It also shows excellent rate capability and cycle durability.Nitrogen-doped porous carbons are very simply prepared by direct pyrolysis of a nitrogen-containing organic salt, the tetrasodium salt of ethylenediamine tetraacetic acid for example, at 600–900 °C in an inert atmosphere without activation. The porosity and surface chemistry of the carbon depend strongly on the pyrolysis temperature. The surface area and pore volume increase with the pyrolysis temperature, and vary from 408 to 1171 m2 g−1 and 0.209 to 0.709 cm3 g−1, respectively. While the nitrogen content decreases from 8.59 at% for pyrolysis at 600 °C to 1.02 at% at 900 °C. The unique microstructure and nitrogen functionalities enable the carbon to exhibit a capacitance of 245 F g−1 in a 6 mol L−1 KOH aqueous electrolytes, which is attributed to the contributions of double layer capacitance and pseudo-capacitance, with an excellent rate capability (188 F g−1 remained at 20 A g−1) and cycle durability.
Co-reporter:Yuhong Jin, Shuo Huang, Mei Zhang, Mengqiu Jia, Dong Hu
Applied Surface Science 2013 Volume 268() pp:541-546
Publication Date(Web):1 March 2013
DOI:10.1016/j.apsusc.2013.01.004
Abstract
The green and efficient synthesis of graphene using sodium carbonate (Na2CO3) as a chemical reducing agent was studied. Extensive characterization confirmed the formation of graphene from graphene oxide using a Na2CO3 solution. The C/O atomic ratio of the as-prepared graphene has increased from 2.48 to 8.15 after reduction as determined by X-ray photoelectron spectroscopy. The conductivity of as-prepared graphene sheets is as high as 10 S m−1. After electrochemical measurements, gravimetric capacitances of 228 and 166 F g−1 at current densities of 5 and 25 mA cm−2, respectively, were obtained with KOH electrolyte.
Co-reporter:Yuhong Jin, Shuo Huang, Mei Zhang, Mengqiu Jia
Synthetic Metals 2013 Volume 168() pp:58-64
Publication Date(Web):15 March 2013
DOI:10.1016/j.synthmet.2013.02.007
An easy and one-pot method for the preparation of sulfonated graphene–polyaniline nanofiber (SGEPA) composites by oil/water interfacial polymerization was studied in this work. Among the composites were obtained at different mass ratios of graphene and aniline. The chemical structure of the materials was characterized by Fourier transform infrared spectroscopy and X-ray diffraction. The morphology of the material was studied by scanning electron microscope and high resolution transmission electron microscopy. The SGEPA composite electrodes with a mass ratio of 1:10 showed better electrochemical performance than pure polyaniline nanofiber and graphene. A high specific capacitance of 962 F/g was obtained at a potential scan rate of 2 mV/s and the specific capacitance value of SGEPA-110 retained about 78% after 1000 cycles. It also exhibited a high energy density of 68.86 Wh/kg at a power density of 102 W/kg. The extraordinary electrochemical properties of the composites were attributed to the well-designed structural advantages of binary nanocomposites and the good combination and synergistic effects between graphene and polyaniline.Highlights► Graphene–polyaniline (SGEPA) composite was prepared by interfacial polymerization. ► Polyaniline nanofibers were homogeneously dispersed on the graphene nanosheets. ► SGEPA composite showed a high specific capacitance of 962 F/g at 2 mV/s. ► SGEPA composite electrode showed excellent electrochemical capacitive properties.
Co-reporter:Dahai Gao
Journal of Applied Polymer Science 2013 Volume 128( Issue 6) pp:3619-3630
Publication Date(Web):
DOI:10.1002/app.38372
Abstract
In this study, poly(methylphenylsiloxane) (PMPS) and phenylene-silica based hybrid material with interpenetrating networks was prepared by a two-step sol–gel process. Firstly, in the presence of H2SO4, the phenylene-silica was formed as sol particles with high branching degree by cohydrolysis and condensation of phenylene-bridged monomer, tetraethoxysilane (TEOS), and hexamethyldisiloxane (MM). Then, the intermediate transformed into gel framework in polymer matrix using alkali catalyst, in order to produce a homogenous hybrid material with interpenetrating networks. The structure of prepared hybrid material was characterized by FTIR and NMR, suggesting that phenylene-silica framework was imported into polymer matrix and the hybrid products have a much higher network chain density than neat PMPS. The thermogravimetric analysis (TGA) shows that the prepared materials start to degrade at around 490°C. The results of tensile test indicate that the typical PMPS/phenylene-silica hybrid material has a tensile strength up to 26 MPa and demonstrate a certain degree of flexibility. An increase of phenylene content in phenylene-silica particles tends to produce hybrid materials with improved thermal stability and tensile strength. The hybrid coating films after calcinating at 350 and 400°C for 2 h exhibit a good mechanical performance on adhesion, impact strength and flexibility. Electrochemical impedance spectroscopy (EIS) measurements show that the investigated films have an extremely high electric resistance (1010 Ohm·cm2) and a satisfied impermeability to 3.5 wt % sodium chloride solution. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Co-reporter:Anna M. Mikhailova;Moussa Tamboura
Journal of Coatings Technology and Research 2013 Volume 10( Issue 1) pp:97-108
Publication Date(Web):2013 January
DOI:10.1007/s11998-012-9424-8
Novel heat-resistant coating materials with excellent adhesion properties were prepared by modification of polysiloxane resin (PSil) with a pre-synthesized tailored polyurethane/polyurea copolymer end-capped with siloxane (PU). The modification was achieved by crosslinking the hydroxyl group of PSil and ethoxy group of PU in the presence of di-n-butyltin dilaurate. The chemical structure of PU was analyzed by Fourier Transform Infrared and Hydrogen-1 Nuclear Magnetic Resonance spectroscopic methods. A series of modified silicone resins (MSRs) have been synthesized and investigated. The molecular weights of the resins were determined by means of gel permeation chromatography. The morphology of the MSR studied by scanning electron microscopy has shown that the resin containing 30% of PU has a small particle size and a good particle size distribution. The adhesion and the mechanical properties of the resins containing 20, 30, and 40% of PU have shown a good performance. Using thermogravimetric analysis, the thermal properties and the thermal degradation of the MSR were investigated.
Co-reporter:Mei Zhang, Mengqiu Jia, Yuhong Jin, Xiangrui Shi
Applied Surface Science 2012 Volume 263() pp:573-578
Publication Date(Web):15 December 2012
DOI:10.1016/j.apsusc.2012.09.111
Abstract
We developed one-spot in situ synthesis method to fabricate CoO/reduced graphene oxide (CoO/RGO) nanocomposite by directly employing C4H6O4·Co·4H2O and hydrophilic graphite oxides as raw materials. The electrochemical performances of the as-prepared CoO/RGO nanocomposite were evaluated in coin-type cells. It delivers a high reversible capacity of 740.7 mAh g−1 at 100 mA g−1, and retains a capacity retention of 95% after 50 cycles. Even after 435 cycles at various rates from 100 to 4000 mA g−1, the capacity still retains 577.9 mAh g−1 when the current density is back to 100 mA g−1. The extraordinary performance is ascribed to the well-designed structure of the CoO/RGO nanocomposite. The small-sized, high crystalline and dense CoO nanoparticles uniformly disperse on conductive graphene substrates, supplying large number of accessible active sites for lithium-ion insertion, short diffusion length for lithium ions, good conductivity and strong interfacial interaction between CoO nanoparticles and RGO nanosheets, which are beneficial for high capacity and long cycling stability.
Co-reporter:Qianlei Jiang, Ruisheng Xue, Mengqiu Jia
Applied Surface Science 2012 Volume 258(Issue 8) pp:3854-3858
Publication Date(Web):1 February 2012
DOI:10.1016/j.apsusc.2011.12.044
Abstract
A novel layer-by-layer electrodeposition and heat-treatment approach was attempted to obtain Sn–Sb–Cu film anode for lithium ion batteries. The preparation of Sn–Sb–Cu anodes started with galvanostatic electrochemically depositing antimony and tin sequentially on the substrate of copper foil collector. Sn–Sb and Cu–Sb alloys were formed when heated. The SEM analysis showed that the crystalline grains become bigger and the surface of the Sn–Sb–Cu anode becomes more denser after annealing. The energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis showed the antimony, tin and copper were alloyed to form SnSb and Cu2Sb after heat treatment. The X-ray photoelectron spectroscopy (XPS) analysis showed the surface of the Sn–Sb–Cu electrode was covered by a thin oxide layer. Electrochemical measurements showed that the annealed Sn–Sb–Cu anode has high reversible capacity and good capacity retention. It exhibited a reversible capacity of about 962 mAh/g in the initial cycle, which still remained 715 mAh/g after 30 cycles.
Co-reporter:Anna M. Mikhailova;Moussa Tamboura;Meng Qiu Jia
Silicon 2012 Volume 4( Issue 3) pp:197-208
Publication Date(Web):2012 July
DOI:10.1007/s12633-012-9123-1
Novel silicone-based coating materials were prepared by the copolymerization of alkoxysilanes with pre-synthesized tailored polyurethane/polyurea copolymer end-capped with siloxane. The structure of the pre-synthesized copolymer and that of the obtained silicone-polyurethane/polyurea copolymer (SPPU) with different hard segment (HS) contents were analyzed by an FT-IR spectroscopic method. The molecular weight and molecular weight distribution of the SPUU was determined by Gel Permeation Chromatography (GPC). The thermal properties of the SPUU copolymers were performed by Thermogravimetric Analysis (TGA). The mechanical and adhesion properties of the copolymers were also investigated by standard methods. Their morphology was studied by Scanning Electron Microscopy (SEM). The electrochemical impedance spectroscopy (EIS) evaluation shows that the protective and anticorrosion properties of these coating materials do not strictly depend on the hard HS content.
Co-reporter:Mengqiu Jia;Chaobo Wu;Wei Li ;Dahai Gao
Journal of Applied Polymer Science 2009 Volume 114( Issue 2) pp:971-977
Publication Date(Web):
DOI:10.1002/app.30635
Abstract
A silicone resin with silphenylene units in Si-O-Si backbones was synthesized by hydrolysis-polycondensation of 1,4-bis(hydroxydimethylsilyl)benzene (BHB) with chlorosilanes. The structure and property of this novel silicone resin were characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), thermogarvimetric analysis (TG), scanning electron microscope (SEM), and electrochemical impedance spectrum (EIS). This silicone resin could be applied as the film forming material of coating when it is prepared under the condition of R/Si, Ph/R, and the content of silphenylene units being 1.3, 0.5, and 10 mol %, respectively. GPC, IR, and NMR results show that the silphenylene units have been incorporated into the polymer of silicone resin. The TG analysis indicates that this novel silicone resin has good heat resistance with the onset degradation temperature of 500.3°C and residual weight of 85.6% at 900°C. SEM results demonstrate that the silicone resin with silphenylene units can form full and uniform films, and its surface morphology of clear paints were not damaged by heat below 350°C. EIS analysis reveals that clear paints of the silicone resin with silphenylene units have good resistance to corrosion. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Co-reporter:Yu Wang, Yuhong Jin, Chenchen Zhao, Yuhao Duan, Xinzi He, Mengqiu Jia
Materials Letters (15 March 2017) Volume 191() pp:
Publication Date(Web):15 March 2017
DOI:10.1016/j.matlet.2016.12.072
•SnO2 QDs/GA composite is realized without adding any surfactant and reducing agent.•SnO2 QDs are anchored and dispersed on the surface of graphene aerogel.•SnO2 QDs/GA exhibits a high capacity of 319 mAh g−1 at 50 mA g−1 after 50 cycles.•Rate capacity of SnO2 QDs/GA remains 150 mAh g−1 at 800 mA g−1.A three-dimensional SnO2 quantum dots/graphene aerogel (SnO2 QDs/GA) composite was prepared using a facile and scalable strategy without adding any surfactant and reducing agent .This as-prepared nanocomposite, with zero-dimensional SnO2 QDs (2–5 nm) anchoring and dispersing on the surface of three-dimensional graphene aerogel, exhibits better properties as anode material for sodium ion batteries than bare SnO2 for its higher reversible capacity (319 mAh g−1 at 50 mA g−1 after 50 cycles) and stability (rate capacity still remains 150 mAh g−1 at 800 mA g−1). Such three-dimensional graphene aerogel could not only act as an electronic conductive matrix for the fast transportation of sodium ion and electrons, but also provide double protection against the aggregation and volume changes of SnO2 QDs during cycling.The as-prepared SnO2 QDs/GA anode material for sodium ion batteries exhibits a higher reversible capacity of 319 mAh g−1 at 50 mA g−1 after 50 cycles compared to bare SnO2 sample.
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