磷酸掺杂磺化聚(氟化亚芳基醚)-聚(环氧乙烷)共混膜的制备研究

为提高聚合物电解质膜燃料电池(PEMFC)的高温性能(150℃以上),采用磺化的聚芳基醚(SDF-F)和聚环氧乙烷(PEO)合成了新的共混膜,并使用磷酸掺杂;对新的共混膜进行了表征,并通过测量拉伸强度确定了酸掺杂共混膜的机械强度。结果表明,SDF-F和PEO成功共聚成共混膜且2种聚合物均匀混合,共混膜的磷酸掺杂水平随着PEO含量的增加而增加,当PEO的质量分数为60%时,掺杂的磷酸质量分数可达784%;共混膜的机械强度随着PEO含量的增加而下降,但即便PEO的质量分数为60%时,共混膜的拉伸强度仍有17 MPa。新共混膜能够完全满足高温聚合物电解质膜燃料电池的要求。

磷酸掺杂磺化聚(氟化亚芳基醚)-聚(环氧乙烷)共混膜的电化学性能研究

研究磷酸掺杂的磺化聚(氟化亚芳基醚)(SDF-F)和聚环氧乙烷(PEO)的共混膜的电化学性能。电化学阻抗谱分析EIS测量结果显示,其电导率与温度无关。根据不同质量比的混合膜在不同温度下的单电池性能测试结果,随着PEO含量越高,电池性能越稳定,SDF-F和PEO的质量比为6/4的混合膜的磷酸掺杂水平最低。由此可以推断,SDF-F/PEO混合膜的电池性能与磷酸水平的关系比与高温下的热稳定性关系更大。且在一定温度范围内,随着温度的升高,电极的性能会得到改善,其主要原因是由于温度升高会提高电极反应速率。然而,因为长时间稳定性测试结果表明其耐用性较低,故在高温PEM-FC中的应用的共混膜还需进一步改性。

Improvement of ionic conductivity of solid polymer electrolyte based on Cu-Al bimetallic metal-organic framework fabricated through molecular grafting

A composite solid electrolyte comprising a Cu-Al bimetallic metal-organic framework(CAB),lithium salt(LiTFSI)and polyethylene oxide(PEO)was fabricated through molecular grafting to enhance the ionic conductivity of the PEO-based electrolytes.Experimental and molecular dynamics simulation results indicated that the electrolyte with 10 wt.%CAB(PL-CAB-10%)exhibits high ionic conductivity(8.42×10~(-4)S/cm at 60℃),high Li+transference number(0.46),wide electrochemical window(4.91 V),good thermal stability,and outstanding mechanical properties.Furthermore,PL-CAB-10%exhibits excellent cycle stability in both Li-Li symmetric battery and Li/PL-CAB-10%/LiFePO4 asymmetric battery setups.These enhanced performances are primarily attributable to the introduction of the versatile CAB.The abundant metal sites in CAB can react with TFSI~-and PEO through Lewis acid-base interactions,promoting LiTFSI dissociation and improving ionic conductivity.Additionally,regular pores in CAB provide uniformly distributed sites for cation plating during cycling.

Preparation and properties of PEO/LiClO_4/KH560-SiO_2 composite polymer electrolyte by sol-gel composite-in-situ method

Composite polymer electrolytes based on polyethylene oxide(PEO) were prepared by using LiClO4 as doping salt and silane-modified SiO2 as filler. SiO2 was formed in-situ in (PEO)8LiClO4 matrix by the hydrolysis and condensation reaction of Si(OC4H9)4. The crystallinity,morphology and ionic conductivity of composite polymer electrolyte films were examined by differential scanning calorimetry,scanning electron microscopy,atom force microscopy and alternating current impedance spectroscopy,respectively. Compared with the crystallinity of the unmodified SiO2 as inert filler,that of composite polymer electrolytes is decreased. The results show that silane-modified SiO2 particles are uniformly dispersed in (PEO)8LiClO4 composite polymer electrolyte film and the addition of silane-modified SiO2 increases the ionic conductivity of the (PEO)8LiClO4 more noticeably. When the mass fraction of SiO2 is about 10%,the conductivity of (PEO)8LiClO4-modified SiO2 attains a maximum value of 4.8×10-5 S·cm-1.

Effect of catalyst on structure of(PEO)_8LiClO_4-SiO_2 composite polymer electrolyte films

(PEO)8LiClO4-SiO2 composite polymer electrolytes(CPEs)were prepared by in-situ reaction,in which ethyl-orthosilicate(TEOS)was catalyzed by HCl and NH3.H2O,respectively.The ionic conductivity,the contact angle and the morphology of inorganic particles in the CPEs were investigated by AC impedance spectra,contact angle method and TEM.The conductivities of acid-catalyzed CPE and alkali-catalyzed CPE are 2.2×10-5and 1.1×10-5S/cm respectively at 30℃.The results imply that the catalyst plays an important role in the structure of in-situ preparation of SiO2,and influences the surface energy and conductivity of CPE films directly.Meanwhile,the ionic conductivity is related to the surface energy.

Diffusion of an Antifogging Agent in Polyethylene Film

The diffusion of an antifogging agent, EO/PO (epoxyethane/epoxypropane) copolymer, through apolyethylene PE film was studied using a simple experimental system. It was found that the temperature, concentration of antifogging agent, crystallinity of PE film and film thickness affect the diffusion process.

The Comparison of Amaranth Decolorization Ability for Two Types of Biological Consortia

The two types of biological consortia--real activated sludge and laboratory adapted consortium were immobilized in polyethylene oxide cryogels. Their potential to decolorize the anionic azo dye amaranth in sequencing batch biofilters was studied. At a growing concentration of azo dye （20 mg·L^-1, 25 mg·L^-1, 30 mg·L^-1） the biofilters had a mean feeding rate of 30.32 ± 25.78 mL^-1·h^-1 and 13.76 ：t： 8.33 mL^-1·h^-1, respectively for immobilized adapted consortia （AC） and activated sludge （AS）. The AC-biofilter reached an overall decolorization rate of 0.211 ± 0.14 mg dye.mLLh1 and a decolorization effectiveness of 60.28 ：t： 32.42%. In contrast, the mean values for overall decolorization rate and effectiveness in AS-biofilter were 0.249 ± 0.16 mg dye.mL^-1·h^-1 and 82.48± 14.41%. The system with immobilized activated sludge had more stable process dynamics and higher tolerance to shock azo dye loading in the first stage of the process. The immobilized adapted consortium presented a good ability to adequate response at higher azo dye concentrations and loading.

Copolymerization Kinetics of Ethylene Oxide and Propylene Oxide

The copolymerization kinetics of ethylene oxide and propylene oxide in an atomizing-circulation reactorunder semi-continuous operation is studied which is of great importance for molecular designation. The kineticparameters are obtained by numerical optimization of the kinetic model.

Pattern transition and sluggish cracking of colloidal droplet deposition with polymer additives

Drying of colloidal droplets often develops versatile depositions.We study the drying deposition of both colloidal droplets containing silica nanoparticles and the silica colloidal droplets with polyethylene oxide(PEO) additives.We focus on the effect of polymer additives on the deposition formation and the cracking dynamics by using in-situ microscope observation.With PEO additives,a transition from ring-like deposition to uniform deposition is observed,and the cracking dynamics is greatly reduced.The PEO additives enhance the adsorption of particles at the air-water interface,thus forming the network structure at the interface which blocks the outward capillary flow.This contributes to the uniform deposition.Meanwhile,the multi-distribution of the aggregates size enhances the non-homogeneity of the drying film and consequently results in multi-nucleation of cracks.This reduces the stress accumulation that drives the crack propagation and may be responsible for the sluggish cracking dynamics.

A novel coral-like garnet for high-performance PEO-based all solid-state batteries

As one of the most promising next-generation energy storage devices,the lithium-metal battery has been extensively investigated.However,safety issues and undesired lithium dendrite growth hinder its development.The application of solid-state electrolytes has attracted increasing attention as they can solve safety issues and show great potential to inhibit the growth of lithium dendrites.Polyethylene oxide(PEO)-based electrolytes are very promising due to their enhanced safety and excellent flexibility.However,they suffer from low ionic conductivity at room temperature and cannot effectively inhibit lithium dendrites at high temperatures due to the intrinsic semicrystalline properties and poor mechanical strength.In this work,a novel coral-like Li_(6.25)Al_(0.25)La_(3)Zr_(2)O_(12)(C-LALZO)is synthesized to serve as an active ceramic filler in PEO.The PEO with LALZO coral(PLC)exhibits increased ionic conductivity and mechanical strength,which leads to uniform deposition/stripping of lithium metal.The Li symmetric cells with PLC do not cause a short circuit after cycling for 1500 h at 60℃.The assembled LiFePO_(4)/PLC/Li batteries display excellent cycling stability at both 60 and 50℃.This work reveals that the electrochemical properties of the composite electrolyte can be effectively improved by tuning the microstructure of the filler,such as the C-LALZO architecture.

Electrochemical behavior of hemoglobin in neutral surfactants with different poly(ethylene oxide) unit lengths adsorbed on an electrode

The direct electron transfer and adsorption behavior of hemoglobin(Hb) in a series of surfactants with different poly(ethylene oxide)(PEO) unit lengths on a glassy carbon electrode have been studied.With a surfactant of appropriate PEO unit length,the surfactant film-modified electrode exhibited a more stable adsorption state with a larger surface coverage of Hb and a more positive formal potential,which can be attributed to the effect of hydrogen bonding between proteins and surfactants.The electrochemical behavior of surfactants with different PEO unit lengths is discussed in detail.Moreover,UV-visible spectroscopy demonstrated that the structure of Hb was not destroyed in the surfactant films.The electrocatalytic activity of hydrogen peroxide on three neutral surfactant-modified electrodes has also been investigated.