A surfactant-modified composite separator for high safe lithium ion battery

Separators have been gaining increasing attention to improve the performance of lithium ion batteries(LIBs),especially for high safe and long cycle life.However,commercial polyolefin separators still face the problems of rapid capacity decay and safety issues due to the poor wettability with electrolytes and low thermal stability.Herein,a novel composite separator is proposed by introducing a surfactant of sodium dodecyl thiosulfate(SDS)into the polytetrafluoroethylene(PTFE)substrate with the binder of polyacrylic acid(PAA)through the suction filtration method.The introduction of PAA/SDS enhances the adsorption energy between PTFE substrate and electrolyte through density functional theory calculations,which improves wettability and electrolyte uptake of the separator significantly.The asachieved composite separator enables the LIBs to own high Li^(+)conductivity(0.64×10^(-3)S cm^(-1))and Li^(+)transference number(0.63),further leading to a high capacity retention of 93.50%after 500 cycles at 1 C.In addition,the uniform and smooth surface morphology of Li metal employed the composite separator after cycling indicates that the lithium dendrites can be successfully inhibited.This work indicates a promising route for the preparation of a novel composite separator for high safe LIBs.

A Simple and Rapid Method for the Detection of Non-Ionic Surfactants

A spectrophotometric approach for the detection of non-ionic surfactant (Triton X-100) has been proposed in this paper. This method does not involve extraction of the ion-associate with harmful solvents, but employs adhesion of the ion-association of potassium/non-ionic surfactants complex and tetraphenylporphyrin tetrasulfonic acid obtained by vigorous shaking. The adhered ion-associate was dissolved with water and its absorbance was measured. The sensitivity for Triton X-100 was determined to be 0.146 (expressed as absorbance of 1 mg/L solution). The adhesion tendency of ion-associate was found to be dependent on the water contact angle, which in turn was influenced by a high adhesion of the ion-associate and by low blank values. In this respect, a tetrafluo-roethylene vessel was found to be the most suitable for the detection of non-ionic surfactants. This spectrophotometrical method is simply and rapidly performed by a procedure based on mechanical shaking and can be employed to detect non-ionic surfactants containing more than 7 polyethylene oxide units.

EFFECTS OF NH_4Cl ON THE INTERACTION BETWEEN POLY(ETHYLENE OXIDE) AND IONIC SURFACTANTS IN AQUEOUS SOLUTIONS

The interaction of poly(ethylene oxide)(PEO)with the ionic surfactants,sodium dodecylsulfate(SDS)and cetyltrimethylammonium chloride(CTAC)respectively,in aqueous solutions containing a certain concentration of NH_4Cl, is studied by the viscosity measurement.It has been found that the ion-dipole interaction between PEO and ionic surfactants is changed considerably by the organic salt.For anionic suffactant of SDS,the addition of NH_4Cl into solution strengthens the interaction between PEO and the headgroup o...

Surfactant assisted solvothermal synthesis of LiFePO4 nanorods for lithium-ion batteries

Well-shaped and uniformly dispersed LiFePOnanorods with a length of 400–500 nm and a diameter of about 100 nm, are obtained with participation of a proper amount of anion surfactant sodium dodecyl sulfonate（SDS） without any further heating as a post-treatment. The surfactant acts as a self-assembling supermolecular template, which stimulated the crystallization of LiFePOand directed the nanoparticles growing into nanorods between bilayers of surfactant（BOS）. LiFePOnanorods with the reducing crystal size along the b axis shorten the diffusion distance of Liextraction/insertion, and thus improve the electrochemical properties of LiFePOnanorods. Such prepared LiFePOnanorods exhibited excellent specific capacity and high rate capability with discharge capacity of 151 mAh/g, 122 mAh/g and 95 mAh/g at 0.1C, 1 C and 5 C, respectively. Such excellent performance of LiFePOnanorods is supposed to be ascribed to the fast Lidiffusion velocity from reduced crystal size along the b axis and the well electrochemical conductivity. The structure, morphology and electrochemical performance of the samples were characterized by XRD, FE-SEM, HRTEM, charge/discharge tests, and EIS（electrochemical impedance spectra）.

Metal Ions Induced Vesicle Formation of Single-Chained Hydrocarbon Surfactants with Coordinated Headgroups

The surfactant of N-dodecyliminodipropionate disodium salt has been synthesized, and structure has been well characterized. The properties in aqueous solution have been studied by potentiometric titration, surface tension, transmission electron microscopy （TEM） and uhra-violet （UV） spectra. It was found that N-dodecyliminodipropionate disodium could exist in four species （e. g. cation, zwitterion, monoanion, dianion） in aqueous solution depending on pH,and relative distribution of these ionic species as a function of pH was obtained. The critical micelle concentration （CMC）, determined from the breakpoint of surface tension at different concentrations, is 4. 16 × 10^1 mol/L, and the surface tension at CMC is 30 mN/m. It was found that the self-aggregate structures in aqueous solution transformed from micelles to vesicles after the Cu （Ⅱ） added. The experimental results showed that coordination between the iminodipropionate group and Cu（Ⅱ） resulted to vesicles formation.

THE STUDY ON THE MASS TRANSFER MECHANISM OF EUROPIUM ION THROUGH LIQUID SURFACTANT MEMBRANES

The transfer of trivalent europium ion in a liquid surfactant membrane system is investigated in order toclarify the characteristics of liquid membrane separation process and the availability of this technique forrecovering trivalent lanthanides and actinides.A layered structure model for the emulsion globule is sug-gested.The equations describing the relationship among the effective membrane thickness,the time andother factors are derived and verified experimentally.Results show that under certain conditions the decreas-ing concentration of europium ion in the external phase is proportional to the square root of the time,the acidity of the internal phase and the carrier concentration in the membrane phase.The membrane phase consists of kerosene（solvent）,Span-80（surfactant）and di-（2-ethylhexyl） phosphoricacid（HDEHP,carrier）.The internal phase is dilute nitric acid and the external phase is aqueous solu-tion containing Eu（NO3）3.The mass transfer rate of europium in this system is high and the recovery ofeuropium may be more than 99%.

Effects of Hydroxyl Groups in Organic Ammonium Counterions on the Properties of Fluorinated Surfactants

The surface tension, foaming and viscosity for C7F15COO^-N^＋H（C2H4OH）χ（C2Hs）3-x and C8F17SO3- N^＋H（C2H4OH）χ（C2H5）3-χ （x = 0, 1, 2, 3） were measured to systematically study the effects of hydroxyl groups in organic ammonium counterions on the properties of perfluorooctanoates and perfluorooctanesulfonates. The results showed that the critical micelle concentration （cmc） and the surface tension at cmc （γcmc） were both increased with the increase of number of hydroxyl groups （χ） in the two series. The perfluorooctanesulfonate had smaller cmc but higher γ=cmc than perfluorooctanoate with the same counterion. The minimum molecular area of surface adsorption （Amin） of C8F17zSO3^-N^＋H（C2H4OH）χ（C2H5）3-χ were 0.64, 0.57, 0.63 and 0.72 nm^2 while the Amin values of C7F15COO^-N^＋H（C2H4OH）χ（C2H5）3-χ were 0.61, 0.62, 0.61 and 0.71 nm^2 when χ = 0, 1, 2 and 3, respectively. For the investigated systems of surfactants, the results of foam expansion ratio agreed with those of surface activity, while the 25% drainage time were consistent with the results of viscosity.

金属离子Mn^(2+)对α-烯烃磺酸钠/月桂酰胺丙基羟磺基甜菜碱蠕虫状胶束形成的调控作用研究

Mn^(2+)可诱导阴离子表面活性剂α-烯烃磺酸钠(AOS)与两性离子表面活性剂月桂酰胺丙基羟磺基甜菜碱(LHSB)的混合物形成蠕虫状胶束。在表面活性剂质量分数1%~5%范围内,研究了AOS与LHSB质量比、Mn^(2+)质量分数、表面活性剂质量分数及温度对蠕虫状胶束黏弹性的影响。结果表明,随着AOS与LHSB质量比从1:9变为9:1以及Mn^(2+)质量分数的增加,表面活性剂溶液黏度先增大后减小。体系的零剪切黏度随表面活性剂质量分数指数增加。常温下研究了表面活性剂黏度的变化规律,测得AOS与LHSB质量比为3:7时体系黏度最大,且当表面活性剂质量分数为2%时的最佳Mn^(2+)含量为0.5%,此时零剪切黏度为9030.9 mPa·s。用冷冻透射电镜(cryo-TEM)观察胶束形态,发现此时溶液中蠕虫状胶束较长,网络结构紧密,呈现出良好的线性黏弹性。表面活性剂质量分数、Mn^(2+)质量分数对蠕虫状胶束的形成有较大影响。

表面活性剂辅助水热合成钼酸镧钠负极材料及性能研究

通过表面活性剂辅助水热合成了钼酸镧钠负极材料,利用X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、循环伏安(CV)测试等对样品结构和电化学性能进行了研究.结果表明,与pH=10相比,pH=6时制备的钼酸镧钠负极材料具有更好的电化学性能,其在电流密度为0.1 A/g时,容量可达356.7 mAh/g,循环后库伦效率接近100%.

不同反离子脂肪醇硫酸盐性能研究

研究了不同反离子的C_(12-14)脂肪醇硫酸盐[脂肪醇硫酸锂(AS-Li)、脂肪醇硫酸钠(AS-Na)、脂肪醇硫酸钾(AS-K)]的性能,包括平衡表面张力、动态表面张力、泡沫、润湿和乳化性能。结果表明:临界胶束浓度时的表面张力按照AS-Li>AS-K>AS-Na顺序降低;AS-Li和AS-Na初始动态表面张力低于AS-K;泡沫体积按照AS-Na>AS-K>AS-Li的顺序降低;润湿时间按照AS-Li<AS-Na<AS-K的顺序增加;AS-Li的乳液稳定性比AS-Na和AS-K差。

Removal of cadmium ions from aqueous solution via micellar-enhanced ultrafiltration

To separate cadmium ions from aqueous solution efficiently, micellar-enhanced ultrafiltration(MEUF) of hollow ultrafiltration membrane was used, with sodium dodecyl benzene sulfonate (SDBS) and sodium dodecyl (sulfate) (SDS) as surfactants. The important parameters affecting the rejection of cadmium, the permeate flux and the secondary resistance were investigated, including surfactant species, surfactant concentration, operating time, trans-membrane pressure, the addition of electrolyte and solution pH. The results show that the rejection rate of cadmium reaches 97.8%. Trans-membrane pressure and the addition of electrolyte (NaCl) are less influential while surfactant species, surfactant concentration and pH value are important for micellar-enhanced ultrafiltration. The optimum concentration of surfactant is the critical micelle concentration, and SDBS is better than SDS. (Micellar-)(enhanced) ultrafiltration with SDBS can separate cadmium ions from aqueous solution efficiently.

Adsorption characteristics of zinc ions on sodium dodecyl sulfate in process of micellar-enhanced ultrafiltration

To separate zinc ions from aqueous solution efficiently, micellar-enhanced ultrafiltration(MEUF) of hollow ultrafiltration membrane was used with sodium dodecyl sulfate(SDS) as surfactant.The formation of micellar and the adsorption mechanism were investigated, including the influence of the ratio of SDS to zinc ions on the micelle quantity, the micelle ratio, the gross adsorptive capacity, the rejection of zinc ions and the adsorption isotherm law. The results show that the rejection rate of zinc ions reaches 97% and the adsorption of zinc ions on SDS conforms to the Langmuir adsorption isotherm and the adsorption is a chemical adsorption process.

Ion Flotation of Scandium

Scandium was recovered from dilute chloride solutions with potassium salt of saturated C_8～C_(12)fatty acids as surfactant by Ion flotation.The optimum comprehensive results of physical properties,stability and scandium concentration of the foam formed with potassium caprate CH_3(CH_2)_8 COOK can be obtained.Re- covery of scandium in the foam was 98% at pH 3.8～5.0 and 25～55℃.The experimental results of 0.3 L/min airflow rate was satisfactory for flotation column.It is of a great potential for using ion flotation technique to concentrate scandium from dilute solutions.

Study on a New Method of Extraction of Metal Ions from SolidMatrices by Supercritical Fluid

8-Hydroxyquinoline, methanol and Triton-100 were first used together in the extraction of metal ions by supercritical CO2. In the new system, the effects of pressure, temperature and the volume of CO2 on the efficiency of supercritical fluid extraction (SFE) were systematically investigated. The recovery under the optimum condition was only 11.38%, but if suitable concentration of methanol (v/v=5%) was added to the supercritical CO2, the recovery was increased significantly (83.60%, RSD=4.37%, n=5). In order to further enhance the recovery Triton X-100 was added to the samples, and the results were satisfactory (96.62%, RSD=2.85%, n=5).

Adsorption of Rare Earth Ion La(Ⅲ) on Yunnan Bowl Tea Surface from Aqueous Solution

The adsorption characteristics of rare earth ion La(Ⅲ) on Yunnan bowl tea surface from aqueous solution and effects of various surfactants on the adsorption were studied. It was found that Yunnan bowl tea can adsorb strongly La(Ⅲ) and pH may affect drastically the adsorption amount of La(Ⅲ). The adsorption law of La(Ⅲ) on Yunnan bowl tea surface follows the Langmuir equation. The maximum adsorption amount of La(Ⅲ) can reach 15 mg·g (-1). A comprehensive adsorption model is suggested according to the experimental results.

Novel additives for the separation of organic acids by ion-pair chromatography

This paper proposes the use of novel surfactant additives for the separation of organic acids by ion-pair chromatography and studies the influences of surfactants on the chromatographic separation behaviors.Researches have been carried out on both silica gel matrix and polymer supporters in order to compare the two ordinary kinds of stationary phases,and the phenomenon is similar. Separation is based on differences in the stabilities of analyte-additive complexes in solution.Retention times of analytes can ...

叔胺型响应表面活性剂的合成及性能研究

以油酸和N,N-二甲基-1,3-丙二胺为原料,氟化钠为催化剂,合成了一种具有CO_(2)响应性的长链叔胺(油酸酰胺丙基二甲基叔胺(DMOA)),测定了其通入CO_(2)和N2下的电导率,证实了合成的DMOA溶液具有CO_(2)响应性能。测定了在通入CO_(2)下DMOA与反离子复配的表面张力,发现将DMOA与二元反离子草酸钠复配能显著降低溶液的表面张力。研究了DMOA与草酸钠复配体系的黏度的CO_(2)响应性能,结果表明,复配体系能够显著提高体系的黏度,并具有CO_(2)响应性和循环可逆性。研究了复配体系的起泡性能和在石蜡膜上的接触角,发现在通入了CO_(2)条件下,复配体系能够降低起泡性能和与疏水表面的接触角。

蚜虫莫氏黑粉菌脂肪酶的酶学性质研究

为明确蚜虫莫氏黑粉菌脂肪酶的应用价值,研究了反应温度、pH值、金属离子、表面活性剂、抑制剂和有机溶剂等对脂肪酶活性的影响。结果表明:蚜虫莫氏黑粉菌脂肪酶的最适反应温度为70℃、pH值为8,具有较好的温度稳定性和pH耐受性,是一种常温发酵合成的耐高温碱性脂肪酶;Zn2+对其活力具有显著的抑制作用;吐温-20、吐温-80、曲拉通-100等表面活性剂和甲醇、乙醇、正丙醇、异丙醇、丙酮等有机溶剂对脂肪酶活力均表现出明显的促进作用;该脂肪酶对三油酸甘油酯的水解无位置特异性;水解对硝基苯酚棕榈酸酯(p-NPP)的米氏常数Km为1.14 mmol/L,最大反应速率vmax为119.05 mol/min。蚜虫莫氏黑粉菌脂肪酶在高温、弱碱性、有机溶剂等工业反应条件下具有良好的应用前景。

Removal of Ni（ll） ions from wastewater by micellar enhanced ultrafiltration using mixed surfactants

Ni（II） ions were removed from aqueous waste using micellar enhanced ultrafiltration （MEUF） with a mixture of surfactants. The surfactant mixture was the nonionic surfactant Tween 80 （TW80） mixed with the anionic surfactant sodium dodecyl sulfate （SDS） in different molar ratios ranging from 0.1-1.5. The opera- tional variables of the MEUF process such as pH, applied pressure, surfactant to metal ion ratio and nonionic to ionic surfactant molar ratio （α） were evaluated. Rejection of Ni and TW80 was 99% and 98% respectively whereas that for SDS was 65%. The flux and all resistances （fouling resistance, resistance due to concentration polarization） were measured and calculated for entire range of α respectively. A calculated flux was found to be declined with time, which was mainly attributed to concentration polarization rather than resistance from membrane fouling.

Effect of synergistic adsorption of anion surfactants and heavy metal ions onto kaolinite surfaces

The experiments were performed in solution for the synergistic adsorption of dodecylbenzene sulfonate and copper ions onto kaolinite surfaces. The results showed that the former enhances the binding constant of copper ions onto kaolinite surfaces, but copper ions deduce the binding constant of dodecylbenzene sulfonate onto kaolinite surfaces. At the same time, they depress the proton release or absorb each other during their adsorption on kaolinite surfaces.