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Critical role of corrosion inhibitors modified by silyl ether functional groups on electrochemical performances of lithium manganese oxides

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Journal of Energy Chemistry 2020年第12期29卷 425-433页

作者： min ji Seong Taeeun Yim Department of Chemistry Incheon National UniversityYeonsu-gu 22012IncheonRepublic of Korea Research Institute of Basic Sciences College of Natural ScienceIncheon National UniversityYeonsu-gu 22012IncheonRepublic of Korea

Lithium manganese oxides(Li Mn2 O4, LMO) have attracted significant attention as important cathode materials for lithium-ion batteries(LIBs), which require fast charging based on their intrinsic electrochemical properties. However, these properties are limited by the rapid fading of cycling retention, particularly at high temperatures, because of the severe Mn corrosion triggered by the chemical reaction with fluoride(F-) species existing in the cell. To alleviate this issue, three types of silyl ether(Si–O)-functionalized task-specific additives are proposed, namely methoxytrimethylsilane, dimethoxydimethylsilane, and trimethoxymethylsilane. Ex-situ NMR analyses demonstrated that the Si-additives selectively scavenged the F-species as Si forms new chemical bonds with F via a nucleophilic substitution reaction due to the high binding affinity of Si with F-, thereby leading to a decrease in the F concentration in the cell. Furthermore, the addition of Si-additives in the electrolyte did not significantly affect the ionic conductivity or electrochemical stability of the electrolyte, indicating that these additives are compatible with conventional electrolytes. In addition, the cells cycled with Si-additives exhibited improved cycling retention at room temperature and 45 °C. Among these candidates, a combination of MTSi and the LMO cathode was found to be the most suitable choice in terms of cycling retention(71.0%), whereas the cell cycled with the standard electrolyte suffered from the fading of cycling retention triggered by Mn dissolution(64.4%). Additional ex-situ analyses of the cycled electrodes using SEM, TEM, EIS, XPS, and ICP-MS demonstrated that the use of Si-additives not only improved the surface stability of the LMO cathode but also that of the graphite anode, as the Si-additives prevent Mn corrosion. This inhibits the formation of cracks on the surface of the LMO cathode, facilitating the formation of a stable solid electrolyte interphase layer on the su

关键词： Lithium-ion batteries Lithium manganese oxide cathode Electrolyte additive Corrosion Silyl ether Fluoride scavenger

Effects of different Ca^(2+) behavior patterns in the electric field on membrane fouling formation and removal of trace organic compounds

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Journal of Environmental Sciences 2022年第1期34卷 292-300页

作者： Zhen Du min ji Ruying Li School of Environmental Science and Engineering Tianjin UniversityTianjin 300350China

The effects of Ca^(2+) on membrane fouling and trace organic compounds(TrOCs)removal in an electric field-assisted microfiltration system were investigated in the presence of Na^(+) alone for *** the electric field,negatively charged bovine serum albumin(BSA)migrated towards the anode far away from the membrane surface,resulting in a 42.9%transmembrane pressure(TMP)reduction in the presence of Na^(+) at 1.5 *** contrast,because of the stronger charge shielding of Ca^(2+),the electrophoretic migration of BSA was limited and led to a neglectable effect of the electric field(1.5 V)on membrane ***,under 3 V applied voltage,the synergistic effects of electrochemical oxidation and bridging interaction between Ca^(2+) and BSA promoted the formation of denser settleable flocs and a thinner porous cake layer,which alleviated membrane fouling with a 64.5%decrease in TMP and nearly 100%BSA *** Tr OCs elimination increased with voltage and reached29.4%–80.4%at 3 *** electric field could prolong the contact between Tr OCs and strong oxidants generated on the anode,which enhanced the Tr OCs ***,a stronger charge shielding ability of Ca^(2+) weakened the electric field force and thus lowered the Tr OCs removal.

关键词： Electric field Membrane fouling Ca^(2+) Flocs formation Trace organic compounds

Synthesis and Crystal Structure of Co(DMSO)_2(H_2O)_2(SCN)_2 with One-dimensional Hydrogen-bonded Structure (DMSO = Dimethylsulfoxide)

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Chinese Journal of Structural Chemistry 2006年第6期25卷 643-646页

作者： WEI Rong-min CHE Yun-Xia ZHENG ji-min Departmentof Biology Chemistry Tianjin Normal University Tianjin 300071 China

The title complex Co（DMSO）2（H2O）2（SCN）2 has been prepared and structurally characterized. It crystallizes in monoclinic, space group P21/n with a= 5.1981（9）, b = 11.944（2）, c = 12.646（2） A,β = 98.686（2）°, V = 776.2（2） A^3, C6H16CoN2O4S4, Mr = 367.38, Z = 2, De = 1.572 g/cm^3, F（000） = 378 and μ（MoKa） = 1.646 mm^-1. The structure was refined to R= 0.0232 and wR = 0.0645 for 1241 observed reflections with I 〉 2σ（I）. In the title complex, each Co（II） atom is octahedrally coordinated by four O atoms from two DMSO ligands and two water molecules as well as two N atoms from SCN^- ions. The title molecules are connected to each other through intermolecular hydrogen bonds to form a 1-D structure extended by eight-membered Co2O4H2 rings.

关键词： dimethylsulfoxide thiocyanate group supramolecule,complex intermolecular hydrogen bond

Impact of photoneutrons on reactivity measurements for TMSR-SF1

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Nuclear Science and Techniques 2017年第6期28卷 101-107页

作者： Rui-min ji ming-Hai Li Yang Zou Gui-min Liu Shanghai Institute of Applied Physics Chinese Academy of Sciences University of Chinese Academy of Sciences

The solid-fueled thorium molten salt reactor(TMSR-SF1) is a 10 MW_(th) test reactor design to be deployed in 5-10 years by the TMSR *** design combines coated particle fuel and molten FLiBe coolant for great intrinsic safety features and economic *** to a large amount of beryllium in the coolant salt,photoneutrons are produced by(y,n) reaction,hence the increasing fraction of effective delayed neutrons in the core by the photoneutrons originating from the long-lived fission *** of the delayed photoneutron groups are of long lifetime,so a direct effect is resulted in the transient process and reactivity *** study the impact of photoneutrons for TMSR-SF1,the effective photoneutron fraction is estimated using k-ratio method and performed by the Monte Carlo code(MCNP5) with ENDF/B-Ⅶ cross *** on the coupled neutronphoton point kinetics equations,influence of the photoneutrons is *** results show that the impact of photoneutrons is not negligible in reactivity *** considering photoneutrons in on-line reactivity measurement based on inverse point kinetics can result in overestimation of the positive reactivity and underestimation of the negative *** photoneutrons also lead to more waiting time for the doubling time *** the photoneutron precursors take extremely long time to achieve equilibrium,a "steady" power operation may not directly imply a "real" criticality.

关键词： TMSR-SF1 Delayed photoneutrons Coupled neutron-photon point kinetics Reactivity measurement

Analysis of Seismic Response for Vugular Reservoir Physical Model Data

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石油地球物理勘探 2009年第A02期44卷 79-85页

作者： ji min National Lab of Oil Resource and Survey China University of Petroleum (Beijing) Beijing 102249 China. Key Lab of Geophysical Prospecting China University of Petroleum (Beijing) Beijing 102249 China

Fulvic acid degradation using nanoparticle TiO_2 in a submerged membrane photocatalysis reactor

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Journal of Environmental Sciences 2005年第6期17卷 942-945页

作者： FU jian-feng ji min AN Ding-nian School of Environmental Science and Engineering Tianjin University Tianjin 300072 China

The degradation of fulvic acid（FA） by nanoparticle TiO2 in a submerged membrane photocatalysis（SMPC） reactor was studied. In this reactor, photocatalytic oxidation and membrane separation co-occured. The continuous air supplier provided O2 for the photocatalytical reaction and mixed the solution through an airflow controller. The particle TiO2 could automatically settle due to gravity without particle agglomeration so it could be easily separated by microfiltration（MF） membrane. It was efficient to maintain high flux of membranes. The effects of operational parameters on the photocatalytic oxidation rate of FA were investigated. Results indicated that photocatalyst at 0.5 g/L and airflow at 0.06 m^3/h were the optimum condition for the removal of fulvic acid, the removal efficiency was higher in acid media than that in alkaline media. The effects of different filtration duration on permeate flux rate of MF with P25 powder and with nanoparticle TiO2 were compared. Experimental results indicated that the permeate flux rate of MF was improved and the membrane fouling phenomenon was reduced with the addition of nanoparticle TiO2 catalyst compared with conventional P25 powder. Therefore, this submerged membrane photocatalysis reactor can faciliate potential application of photocatalytic oxidation process in drinking water treatment.

关键词： fulvic acid microfiltration membrane nanoparticle TiO2 photocatalytic oxidation reactor

Estimation of plasma density perturbation from dusty plasma injection by laser irradiation on tungsten target in DiPS

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Plasma Science and Technology 2020年第4期22卷 90-96页

作者： In Je KANG min-Keun BAE In Sun PARK min ji LEE Kyu-Sun CHUNG Department of Electrical Engineering Hanyang UniversitySeoul 133791Republic of Korea Plasma Technology Research Center National Fusion Research InstituteGunsan 54004Republic of Korea

To investigate the interaction of dusty plasma with magnetized plasmas at divertor plasma simulator,radial profiles of plasma density(ne)and electron temperature were measured in terms of plasma discharge currents and magnetic flux intensity by using a fast scanning probes system with triple *** plasma with dusts(a generation rate of 3μg s-1 and a size of 1–10μm)was produced via interactions between a high-power laser beam and a full tungsten *** ne increases,the scale of the effects of dusty plasma injection on magnetized plasmas was ***,the duration of transient fluctuation was *** numerical estimation of plasma density perturbation due to dusty plasma injection,the result was 10%at a core region of the magnetized plasma with ne of(2–5)×10^11 cm^-3 at steady state condition.

关键词： plasma density perturbation dusty plasma tungsten dust DiPS

An Analytical Study of Three-State Potts Model on Lattice

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Communications in Theoretical Physics 2006年第5期45卷 877-881页

作者： ZHAO Pei-Ying WU ji-min Institute of High Energy Physics the Chinese Academy of Sciences Beijing 100049 China

We investigate the phase structure of the three-state Ports model by the variational cumulant expansion approach, it is shown that there is a weak first-order phase transition in three and four dimensions. The critica... 详细信息

关键词： variational cumulant expansion Potts model phase structure

STUDY OF THE FLOWTHROUGH NON-SUBMERGED VEGETATION

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Journal of Hydrodynamics 2005年第4期17卷 498-502页

作者： NEHAL Laounia YAN Zhong-min XIA ji-hong College of Water Conservancy and Hydropower Engineering Hohai University Nanjing 210098 China

Vegetation is an important feature of many rivers. Vegetation along rivers produces high resistance to flow and, as a result, has a large impact on water levels in rivers and lakes. The effects of instream-unsubmerged vegetation （such as the reed-similar Kalmus） on flow resistance and velocity distributions is studied in the paper. Artificial vegetation is used in the experimental study to simulate the Acorus Calmus L. As shown in experimental tests the resistance depends strongly on vegetation density and the Manning resistance coefficient varies with the depth of flow. A simplified model based on concepts of drag is developed to evaluate the roughness coefficient （Manning＇s n） for non submerged vegetation. In vegetated channels the overall flow resistance is influenced significantly by the distribution pattern of the vegetated beds. Within vegetation, vertical variation in velocity is different from that in the non vegetated bed, which reflects the variation in vegetation density. Vertical turbulent transport of momentum is negligible as demonstrated by experiments.

关键词： open channel flow non-submerged vegeta-tion vegetation density flow resistance velocity distribution