Li Yang

Shanghai Jiao Tong University, Shanghai, Shanghai Shi, China

Are you Li Yang?

Claim your profile

Publications (50)89.3 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: In this work, a new morphological nanostructure of the CNWs@ultrathin SnO2 NSs@C composite has been successfully fabricated, realizing the integration of two-dimensional ultrathin SnO2 NSs and one-dimensional CNWs. The nanosized ultrathin SnO2 NSs (thickness of ca. 1-3 nm) are uniformly distributed between one dimension CNWs core and C shell, as confirmed by XRD, SEM, TEM and HRTEM characterizations. When tested as potential anode materials for LIBs, the as-prepared coaxial nanocable-like CNWs@ultrathin SnO2 NSs@C composite exhibits outstanding reversible capacity for lithium storage (695 mAh g-1 after 40 cycles at 160 mA g-1, 651 and 618 mAh g-1 after 80 cycles at 400 and 800 mA g-1, respectively). This intriguing architecture, which integrates both electronic conductivity and buffering matrix design strategies, contributing to enhanced lithium storage performance.
    Journal of Power Sources 01/2014; · 4.68 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: An imidazolium-based polymerized ionic liquid (PIL), poly(1-ethyl-3-vinylimidazolium bis(trifluoromethanesulfonylimide)) is successfully synthesized via a new three-step process comprising the direct radical polymerization of the 1-vinylimidazole monomer, and subsequent quaternization reaction followed by an anion exchange procedure. Furthermore, polymer electrolytes are prepared by blending as-obtained PIL as the polymer host with an ionic liquid and LiTFSI salt. Electrochemical measurements demonstrate that compared with polymer electrolytes containing the PIL host synthesized by the conventional route, polymer electrolytes containing the PIL host obtained by new synthetic process exhibit significantly improved capacity and cycling performance, which is due to higher ionic liquid content.
    Journal of Power Sources 01/2014; 258:150–154. · 4.68 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: The mesoporous Li3V2(PO4)3@CMK-3 nanocomposite has been firstly synthesized by a sol–gel method. The X-ray diffraction (XRD), transmission electron microscopy (TEM) and nitrogen adsorption–desorption measurements show that the Li3V2(PO4)3@CMK-3 nanocomposite exhibits the pure monoclinic structure and mesoporous morphology. Li3V2(PO4)3 has particle sizes of <50 nm, and are embedded in the mesoporous channels as well as well dispersed on the CMK-3 surface. Electrochemical measurements demonstrate that the Li3V2(PO4)3@CMK-3 nanocomposite shows significantly better rate capability and cycling performance than the bulk Li3V2(PO4)3. In the potential range of 3.0–4.3 V, the Li3V2(PO4)3@CMK-3 nanocomposite delivers high initial discharge capacity of 130.0 mAh g−1 at 0.2 C, and maintain an initial discharge capacity of 119.5 and 107.8 mAh g−1 at 5 C and 10 C, respectively. After 300 cycles, it can still retain a discharge capacity of 95.4 and 73.5 mAh g−1 at 5 C and 10 C, respectively. The good electrochemical performance for the Li3V2(PO4)3@CMK-3 nanocomposite are related to the special mesoporous structure, nanosized particles, and the existence of conductive carbon matrix, thus leading to improvement in electron and lithium ion diffusivity.
    Journal of Power Sources 01/2014; 253:294–299. · 4.68 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: In this work, a new nanostructure of SnO2 nanoparticles (NPs) encapsulated into hollow TiO2 nanowires (SnO2@TiO2) has been successfully fabricated. This unique architecture intrinsically possess void space in between the TiO2 shell and SnO2 nanoparticle cores, as confirmed by XRD, XPS, SEM, TEM and HRTEM characterizations. The TiO2 shell of the composite can not only alleviate the pulverization and drastic volume change of the SnO2 NPs and maintain the structural integrity, but also contribute to the total capacity of the composite. Moreover, the void space can also accommodate the volume expansion of SnO2 and provide highly efficient channels for the fast transport of both electrons and lithium ion during discharge/charge cycling process. When tested as potential anode materials for lithium ion batteries, the as-prepared hollow TiO2 nanowires shell encapsulating SnO2 NPs architecture exhibits good lithium storage performance and excellent cyclability (which delivers a higher reversible capacity of 445 mAh g−1 at 800 mA g−1 after 500 cycles). The unique architecture should be responsible for the superior electrochemical performance.
    Journal of Power Sources 01/2014; 253:9–16. · 4.68 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: Li2MnSiO4/C composite is prepared by sol–gel method with Mn3O4 nanoparticle, and its carbon content, structure, and morphology are characterized. The results show that Li2MnSiO4/C exhibits pure phase with orthorhombic structure and the size of Li2MnSiO4 (20–30 nm) is smaller than Mn3O4 nanoparticle. As the cathode material of lithium-ion battery, Li2MnSiO4/C delivers an initial discharge capacity of about 240 mAh g−1 at the current density of 8 mA g−1, corresponding to 1.44 mol of Li+ per formula unit. The cycle performance of Li2MnSiO4/C at different current densities from 8 mA g−1–320 mA g−1 is studied, and it is found that the capacity retention is improved with the increasing of current density. Basing on the results of ex-situ X-ray diffraction measurement, it is inferred that low degree of irreversible distortion for Li2MnSiO4 may result in the improved capacity retention at high current density.
    Journal of Power Sources 01/2014; 252:169–175. · 4.68 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: The electrochemical properties of solvent-free, quaternary polymer electrolytes based on a novel polymeric ionic liquid (PIL) as polymer host and incorporating 1g13TFSI ionic liquid, LiTFSI salt and nano-scale silica are reported. The PIL–LiTFSI–1g13TFSI–SiO2 electrolyte membranes are found to be chemically stable even at 80°C in contact with lithium anode and thermally stable up to 320°C. Particularly, the quaternary polymer electrolytes exhibit high lithium ion conductivity at high temperature, wide electrochemical stability window, time-stable interfacial resistance values and good lithium stripping/plating performance. Batteries assembled with the quaternary polymer electrolyte at 80°C are capable to deliver 140mAhg−1 at 0.1C rates with very good capacity retention.
    Lancet. 10/2011;
  • [show abstract] [hide abstract]
    ABSTRACT: Four new functionalized ILs based on piperidinium and pyrrolidinium cations with two ether groups and TFSI− anion are synthesized and characterized. Physical and electrochemical properties of these ILs, including melting point, thermal stability, viscosity, conductivity and electrochemical stability, are investigated. All the ILs are liquids at room temperature, and the viscosities of P(2o1)2-TFSI and P(2o1)(2o2)-TFSI are 55 and 53mPas at 25°C, respectively. Behavior of lithium redox, chemical stability against lithium metal and charge–discharge characteristics of lithium batteries, are also investigated for these IL electrolytes with 0.6molkg−1 LiTFSI. Though the cathodic limiting potentials of these ILs are 0.4V versus Li/Li+, the lithium plating and striping on Ni electrode can be observed for these IL electrolytes, and these IL electrolytes show good chemical stability against lithium metal. Li/LiFePO4 cells using these IL electrolytes without additives have good capacity and cycle property at the current rate of 0.1C, and the cell using the P(2o1)(2o2)-TFSI electrolyte owns good rate property.
    Lancet. 01/2011; 196(13):5637-5644.
  • [show abstract] [hide abstract]
    ABSTRACT: Gel polymer electrolytes composed of PVdF-HFP microporous membrane incorporating a guanidinium-based ionic liquid with 0.8molkg−1 lithium bis(trifluoromethanesulfonylimide) are characterized as the electrolytes in Li/LiFePO4 batteries. The ionic conductivity of these gel polymer electrolytes is 3.16×10−4 and 8.32×10−4Scm−1 at 25 and 50°C, respectively. The electrolytes show good interfacial stability towards lithium metal and high oxidation stability, and the decomposition potential reaches 5.3 and 4.6V (vs. Li/Li+) at 25 and 50°C, respectively. Li/LiFePO4 cells using the PVdF-HFP/1g13TFSI-LiTFSI electrolytes show good discharge capacity and cycle stability, and no significant loss in discharge capacity of the battery is observed over 100 cycles. The cells deliver the capacity of 142 and 150mAhg−1 at the 100th cycling at 25 and 50°C, respectively.
    Lancet. 01/2011; 196(15):6502-6506.
  • [show abstract] [hide abstract]
    ABSTRACT: A unique ordered mesoporous Sn–C composite with Sn nanoparticles confined in carbon nanorods was prepared using SBA-15 as the template. This composite was employed as the anode material of Li-ion batteries, delivering excellent electrochemical properties of high reversible lithium storage capacity (554 mAh g−1 after 200 cycles) and great rate capability (as high as 5000mA g−1).
    Electrochemistry Communications - ELECTROCHEM COMMUN. 01/2011; 13(8):848-851.
  • [show abstract] [hide abstract]
    ABSTRACT: One ether-functionalized guanidinium ionic liquid is used as new electrolytes for lithium battery. Viscosity, conductivity, behavior of lithium redox, chemical stability against lithium metal, and charge–discharge characteristics of lithium batteries, are investigated for the IL electrolytes with different concentrations of lithium salt. Though the cathodic limiting potential of the IL are 0.7V vs. Li/Li+, the lithium plating and striping on Ni electrode can be observed in the IL electrolytes, and the IL electrolytes show good chemical stability against lithium metal. Li/LiCoO2 cells using the IL electrolytes without additives have good capacity and cycle property at the current rate of 0.2C when the LiTFSI concentration is higher than 0.3molkg−1, and the cell using the IL electrolyte with 0.75molkg−1 LiTFSI owns good rate property. The activation energies of the LiCoO2 electrode for lithium intercalation are estimated, and help to analyze the factors determining the rate property.
    Journal of Power Sources 01/2011; 196(3):1433-1441. · 4.68 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: Two new functionalized ionic liquids (ILs) based on guanidinium cation with two ether groups and TFSA− anion are synthesized and characterized. Their physicochemical and electrochemical properties, including melting point, thermal stability, density, viscosity, conductivity, and electrochemical window are determined. Both the ILs are liquids at room temperature, and the viscosities are about 60mPas at 25°C. Behavior of lithium redox, chemical stability against lithium metal and charge–discharge characteristics of lithium battery, are also examined for the two ILs as electrolyte with 0.6molkg−1 LiTFSA. Though the cathodic limiting potentials of the two ILs are higher than 0V versus Li/Li+, the lithium plating and stripping on Ni electrode can be observed in the two IL electrolytes, indicating their good chemical stability against lithium metal. Li/LiFePO4 cells using the two IL electrolytes without any additive showed good cycle property at the current rate of 0.2C at 25°C and 55°C.
    Lancet. 01/2011; 196(24):10658-10666.
  • [show abstract] [hide abstract]
    ABSTRACT: New functionalized ILs based on quaternary ammonium cations with three or four ether groups and TFSI− anion were synthesized and characterized. Physical and electrochemical properties, including melting point, thermal stability, viscosity, conductivity and electrochemical stability were investigated for these ILs. Five ILs with lower viscosity in these ILs were applied in lithium battery as new electrolytes. Behavior of lithium redox and charge–discharge characteristics of lithium battery were investigated for these IL electrolytes with 0.6 mol kg−1 LiTFSI. Lithium plating and striping on Ni electrode could be observed in these IL electrolytes. Li/LiFePO4 cells using these IL electrolytes without additives had good capacity and cycle property at the current rate of 0.1 C, and the N(2o1)3(2o2)TFSI and N2(2o1)3TFSI electrolytes owned better rate property.Research highlights► Some new functionalized ILs with three or four ether groups are reported. ► They have good electrochemical stability. ► Li/LiFePO4 cells using five IL electrolytes have good capacity and cycle property.
    Electrochimica Acta. 01/2011; 56(12):4663-4671.
  • [show abstract] [hide abstract]
    ABSTRACT: Hydrogen was purified by a series of Pd−Ag/ceramic composite membranes with different Pd−Ag alloy thickness ranging from 2.5 to 15 μm. During the process, methane (CH4) was found to be formed in the permeated gas, which was also reported in related studies. A comprehensive study was carried out to identify the source of CH4 by discussing the influence of membrane defect and feed composition with several gas mixtures as feed gas. It was found that CH4 content in the purified hydrogen increased with the defect degree, and for obtaining 99.9% permeated hydrogen, the helium leakage of the membrane should be less than 0.01 mL min−1 cm−2; whereas no helium flow should be detected, that is, the membranes should be completely defect-free, to achieve 99.999+% hydrogen. Meanwhile, different feed gases were used to discover the reason for production of CH4 during purification; the results revealed that only CO in the feed gas resulted in the formation of CH4 on the permeated side. Finally, on the basis of the above findings, a small amount of Au in the Pd−Ag alloy was added to examine the possibility of preventing CH4 formation, and the preliminary result was satisfactory.
    Industrial & Engineering Chemistry Research - IND ENG CHEM RES. 01/2010; 49(9):4377-4382.
  • Bingjia Yao, Li Yang
    [show abstract] [hide abstract]
    ABSTRACT: A new acetic acid separation method was developed through a successful combination of cloud point extraction and complex extraction technology (CPE-SE), where an acetic acid complex compound formed and was solubilized in a surfactant micelle solution, instead of an organic solvent, and then concentrated into one phase by a phase separation process of the CPE technology. Since no organic solvent diluents were used, the new process was environmentally friendly and with a lower cost; meanwhile, the high selectivity of the complex extraction based on chemical complexation and high efficiency of CPE were also inherited as advantages over conventional solvent extraction process. In consideration of the compatibility and the related CPE characteristics, tributyl phosphate and PEG/PPG-18/18 Dimethicone were selected as complexing agent and surfactant of the CPE-SE system, respectively, and the extraction system was optimized by studying the effect of the main process parameters, including surfactant and complexing agent concentration, temperatures for the stirring and incubation steps, on the recovery and the distribution coefficient. A relative high recovery of 71.4% and a distribution coefficient of 1.4 were achieved simultaneously with the optimized process in the treatment of 0.1 M acetic acid solution. Based on its competitive extractability, high efficiency, low-cost, and environment friendlyness, the CPE-SE process was expected to be a potential separation method for a dilute acetic acid solution.
    Separation Science and Technology 01/2009; 44(2):476-490. · 1.16 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: New ionic liquids based on S-alkylthiolanium cations with TFSI anions were synthesized and characterized. The physical and electrochemical properties, including melting point, thermal stability, solubility, viscosity, conductivity and electrochemical window, were reported. Relation between these properties and the structure of the cations was discussed. In this series, T4TFSI and T5TFSI have melting points below −60°C, and their conductivities are 2.10 mS/cm and 1.46 mS/cm; their electrochemical windows are 4.1 V and 4.5 V at room temperature. These cyclic alkylthiolanium-based ionic liquids are promising as novel electrolytes in various electrochemical devices, especially under low temperature condition.
    Chinese Science Bulletin 01/2009; 54(8):1322-1327. · 1.32 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: Eight new functionalized guanidinium ILs based on small cations containing ether group (methoxyethyl group) or ester group (methyl acetate group) and TFSI− anion were synthesized and characterized. Physical and electrochemical properties of these products, including melting point, thermal stability, viscosity, conductivity and electrochemical window, were investigated. All the products were liquids at room temperature, and they had low-melting points. The viscosities of cg1(2o1)TFSI and cg2(2o1)TFSI were 46 and 48mPas at 25°C, respectively. Electrochemical and thermal stabilities of these functionalized guanidinum ILs permitted them to become potential electrolytes used in electrochemical devices.
    Electrochimica Acta - ELECTROCHIM ACTA. 01/2009; 54(17):4269-4273.
  • [show abstract] [hide abstract]
    ABSTRACT: Sixteen new guanidinium salts based on small cations and TFSI− anion were prepared and characterized. Physical and electrochemical properties of these products, including melting point, thermal stability, viscosity, conductivity and electrochemical window were investigated. Reducing symmetry of cations can reduce the melting points, and 12 products are liquids at room temperature. The viscosities of cg22TFSI, cg12TFSI and cg13TFSI were 45, 46 and 52 mPa s at 25 °C, respectively. Electrochemical and thermal stabilities of these ILs permitted them to become promising electrolytes used in electrochemical devices.
    Electrochimica Acta. 01/2009; 54(6):1752-1756.
  • [show abstract] [hide abstract]
    ABSTRACT: Two ionic liquids based on guanidinium cations and TFSA− anion were prepared, and their electrochemical stabilities were investigated. The cathodic limiting potentials of the two ILs were 0.7V versus Li/Li+, and their electrochemical windows were 4.2V. However, the lithium plating and striping on Ni electrode could been observed in the two IL electrolytes containing 0.3molkg−1 of LiTFSA without additive. And Li/LiCoO2 cells using the two IL electrolytes without additive showed good capacity and cycle property at the current rate of 0.2C.
    Journal of Power Sources 01/2009; 191(2):619-622. · 4.68 Impact Factor
  • Chinese Journal of Chemistry - CHINESE J CHEM. 01/2009; 27(11):2159-2165.
  • [show abstract] [hide abstract]
    ABSTRACT: A new asymmetric sulfonium-based ionic liquid, 1-butyldimethylsulfonium bis(trifluoromethylsulfonyl) imide (S114TFSI), was developed as electrolyte material for lithium secondary battery. Its cathodic potential was a little more positive against the Li/Li+, so vinylene carbonate (VC) was added into the LiTFSI/S114TFSI ionic liquid electrolyte to ensure the formation of a solid electrolyte interface (SEI), which effectively prevented the decomposition of the electrolyte. The properties of the Li/LiMn2O4 cell containing S114TFSI-based electrolyte were studied and the cycle performances were compared to those with a conventional organic electrolyte (1 mol/L LiPF6/DMC:EC=1:1(w/w)) at room temperature. Electrochemical impedance spectroscopy (EIS) and X-ray diffraction (XRD) were conducted to analyze the mechanisms affecting the cell performances at different temperatures. The lithium secondary battery system, using the above ionic liquid electrolyte material, shows good cycle performances and good safety at room temperature, and is worthwhile to further investigate so as to find out the potential application.
    Chinese Science Bulletin 04/2008; 53(9):1337-1342. · 1.32 Impact Factor

Publication Stats

100 Citations
89.30 Total Impact Points

Institutions

  • 2005–2014
    • Shanghai Jiao Tong University
      • Department of Chemical Engineering (CHE)
      Shanghai, Shanghai Shi, China
  • 2006–2011
    • Shanghai University
      • Department of Chemical Engineering and Technology
      Shanghai, Shanghai Shi, China