超级电容器准固态聚合物电解质膜的研究

制备了一种介于水凝胶和全固态聚合物电解质之间的聚合物电解质膜,用于活性炭电子双电层电容器。测试表明使用该聚合物电解质膜的双电层电容器的容量为2 15mA·h,其容量、功率特性与KOH水溶液电容器相当。电容器的循环伏安曲线,稳定的充放电循环曲线及交流阻抗谱说明该种聚合物电解质膜在碳基超级电容器的使用电压范围(0～1V)内是稳定的,而且聚合物电解质膜电容器表现出良好的可逆性和循环特性。     

Alkaline direct methanol fuel cell based on a novel anion-exchange composite polymer membrane

The anion-exchange composite polymer membrane based on quaterized poly(vinyl alcohol)/poly(epichlorohydrin) (designated as Q-PVA/PECH) was prepared by a solution casting method and a quaternization process. The characteristic properties of the Q-PVA/PECH anion-exchange composite polymer membranes were investigated by scanning electron microscopy, thermal gravimetric analysis, micro-Raman spectroscopy, and AC impedance method. Alkaline direct methanol fuel cells (ADMFC) comprised Q-PVA/PECH anion-exchange composite polymer membranes were assembled and examined. Experimental results indicate that an alkaline DMFC employing an inexpensive non-perfluorinated Q-PVA/PECH composite polymer membrane shows excellent electrochemical performances. The peak power densities of the DMFC using 4 M KOH + 1 M CH₃OH, 2 M CH₃OH, and 4 M CH₃OH fuels are 17.22, 22.30, and 20.81 mW cm⁻², respectively, under ambient conditions. The Q-PVA/PECH composite polymer membrane appears as a viable candidate for use in an ADMFC.     

A thin-film/agglomerate model of a proton-exchange-membrane fuel cell cathode catalyst layer with consideration of solid-polymer-electrolyte distribution

A thin-film/agglomerate model for the cathode part of a proton-exchange-membrane fuel cell is developed. Parameter estimation is employed to determine the exchange current density in the catalyst layer, proton conductivity of the recast ionomer, and oxygen diffusivity in the solid polymer electrolyte. The effects of catalyst and polymer electrolyte loadings in the catalyst layer on the cell performance are demonstrated using this model. The influence of polymer electrolyte distribution in the catalyst layer is correlated with the oxygen diffusion and proton migration rates within the electrolyte. It is found that proton migration in the polymer electrolyte is the dominant factor for cell current density under normal operating conditions. A better cell performance is achieved by a concentrated polymer electrolyte near the catalyst layer/membrane interface.     

Effect of silica on the interfacial stability of the PEO-based polymer electrolytes

Summary In order to evaluate the effect of silica on stabilizing the interface of lithium metal electrode/solid polymer electrolyte, the cyclic behavior for silica-free and silica-containing polymer electrolyte under electrical stress was investigated using cyclic voltammetry. These electrolytes have an ionic conductivity of the order 10^-4 S/cm at above 60°C and most importantly the introduction of hydrophilic silica in PEO-based polymer electrolyte has brought about the enhanced stability of lithium metal electrode/polymer electrolyte interface especially under electrical stress. This in turn supports the suitability of the composite polymer electrolytes with hydrophilic silica for fabrication of enhanced rechargeable solid lithium polymer batteries. Received: 7 May 2002/ Revised version: 10 July 2002/ Accepted: 12 July 2002     

New ionic polymer–metal composite actuators based on PVDF/PSSA/PVP polymer blend membrane

Ionic polymer–metal composite (IPMC) actuators that display continuously large actuation displacements without back relaxation and with large blocking force at low direct current (DC) voltages are used as biomimetic sensors, actuators and biomedical devices. This article reports the preparation and actuation performance of new IPMC actuators based on the polyvinylidene fluoride (PVDF)/polystyrene sulfonic acid (PSSA)/polyvinyl pyrrolidone (PVP) polymer blend membrane, which requires low voltage DC. The performance results of the proposed IPMC actuators are compared with Nafion‐based IPMC actuators. In the blend membrane, PVDF is the hydrophobic polymer, PSSA is the polyelectrolyte, and PVP is the hydrophilic basic polymer. The proposed IPMC actuators based on the PVDF/PSSA/PVP blend membrane of polymer mixture ratios of 60/15/25 and 50/25/25 gave higher actuation displacement and higher blocking force at low DC voltages than the Nafion‐based IPMC actuator. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

原位构建富氟SEI的凝胶电解质用于金属锂二次电池

以六氟磷酸锂（LiPF₆）为四氢呋喃的聚合引发剂制备凝胶电解质,同时作为氟源在金属锂负极表面原位构建富含LiF的固态电解质界面层（solid electrolyte interface,SEI）来抑制锂枝晶的生长以及金属锂/电解液之间的副反应。所制备的凝胶电解质具有较高的室温离子电导率（1.33 mS·cm^-1）和较宽的电化学稳定窗口（4.5 V）。原位聚合方式组装金属锂对称电池循环后,锂负极表面没有明显的锂枝晶和被损毁的形貌出现;XPS结果表明锂负极表面生成了富含LiF的SEI。组装的LiFePO₄全电池在1 C的电流密度下,稳定循环400周后仍保持118.7 mAh·g^-1的放电比容量。得益于四氢呋喃在开环聚合反应过程中,促进了LiPF₆分解反应平衡的正向移动,在锂负极表面形成稳定的富含LiF的SEI,能够抑制锂枝晶的生长并防止其被持续性的腐蚀破坏。     

Inherently adaptive polymer nanocomposites

A new class of inherently adaptive polymer nanocomposites is developed where stress‐enabled redox reactions are used in the context of a solid polymer electrolyte to form deposits which render mechanical strengthening effects. Experimental investigations were conducted to provide insight into this self‐adaptation phenomenon. Results of tests conducted on bolted composite joints demonstrated the occurrence of this self‐adaptation phenomenon. Experiments were also performed on cracked composite specimens where the potential of the self‐adaptation phenomenon to repair cracks was demonstrated. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40620.     

Electro-active graphene–Nafion actuators

Electro-active actuators based on graphene reinforced Nafion composite electrolytes were developed and their electro-chemo-mechanical properties and actuation performances were investigated. The tensile strength of the graphene–Nafion ionic membrane was significantly improved up to 200% within 1.0 wt.% loading, and Young’s modulus was more than two times with a minute loading of graphene to Nafion electrolyte. The proton conductivity and the water-uptake ratio were greatly improved, while apparent changes in the ion exchange capacity were not observed. Morphological tests, chemical techniques, and scattering techniques were used to study the interaction mechanism between graphene and Nafion, resulting in great improvements of the actuation performances. Present results show that a minute loading of graphene greatly improves the harmonic responses, the blocking force and the energy efficiency in Nafion-based ionic polymer–metal composite actuators.     

Lithium polymer batteries using the highly porous membrane filled with solvent-free polymer electrolyte

Solid polymer electrolyte supported by a microporous membrane was prepared and characterized. The polymer electrolyte was prepared by penetrating the highly conductive solvent-free polymer electrolyte based on poly(oligo [oxyethylene] oxyterephthaloyl) into the pores of the highly porous membrane. The electrochemical characteristics of the solid polymer electrolytes are presented, and we discuss the possibility of them as an electrolyte material for lithium polymer batteries.     

原位构建富氟SEI的凝胶电解质用于金属锂二次电池

以六氟磷酸锂（LiPF₆）为四氢呋喃的聚合引发剂制备凝胶电解质,同时作为氟源在金属锂负极表面原位构建富含LiF的固态电解质界面层（solid electrolyte interface,SEI）来抑制锂枝晶的生长以及金属锂/电解液之间的副反应。所制备的凝胶电解质具有较高的室温离子电导率（1.33 mS·cm^-1）和较宽的电化学稳定窗口（4.5 V）。原位聚合方式组装金属锂对称电池循环后,锂负极表面没有明显的锂枝晶和被损毁的形貌出现;XPS结果表明锂负极表面生成了富含LiF的SEI。组装的LiFePO₄全电池在1 C的电流密度下,稳定循环400周后仍保持118.7 mAh·g^-1的放电比容量。得益于四氢呋喃在开环聚合反应过程中,促进了LiPF₆分解反应平衡的正向移动,在锂负极表面形成稳定的富含LiF的SEI,能够抑制锂枝晶的生长并防止其被持续性的腐蚀破坏。     

锂电池用PEO基固态聚合物电解质研究进展及应用

介绍了锂电池用聚氧化乙烯(PEO)基固态聚合物电解质的研究进展,论述了国内外在PEO改性、锂盐改进和制备PEO-无机复合聚合物电解质等三方面在提高其电导率、电化学稳定窗口和离子迁移数等性能进行的研究,综述了PEO基聚合物电解质的应用情况.     

高温质子交换膜燃料电池用离子液体聚合物电解质的研究进展

综述了近十几年来高温质子交换膜燃料电池用离子液体聚合物电解质的研究进展及其在高温质子交换膜燃料电池中的应用进展,指出了此类电解质目前存在的亟待解决的两个问题：咪唑类离子液体毒化Pt基催化剂和复合膜中离子液体的长期稳定性。最后对高温质子交换膜燃料电池用离子液体聚合物电解质的发展前景作了展望,即开发与Pt基催化剂相容的离子液体聚合物电解质以及预防复合膜内离子液体的流失,即提高高温质子交换膜燃料电池的性能及长期稳定性,最终提高高温燃料电池的寿命。     

高分子聚合物在太阳能电池电解质中的应用

介绍了高分子聚合物作为电解质在染料敏化纳米晶TiO2太阳能电池中的应用研究进展,按电解质的物理状态不同,分别对高分子聚合物凝胶准固态电解质和导电高分子聚合物固态电解质进行了综述,并对存在的问题和未来的研究方向进行了探讨。     

SiO_2掺杂（PEO）_8-LiClO_4固体电解质的性能研究

通过正硅酸乙酯水解得到的SiO2溶胶,掺杂于（PEO）8-LiClO4固体电解质体系中。得到厚度约为130μm性能良好的聚合物电解质薄膜,利用交流阻抗法测定聚合物电解质的电导率,通过红外光谱对聚合物电解质薄膜的基团状态进行分析研究。结果表明掺杂SiO2后（PEO）8-LiClO4固体电解质的室温电导率有很大提高,在SiO2质量分数为10%时最高,达到2.522×10-6S/cm;温度的升高有利于电导率的提升,电导率与温度关系遵循Arrhenius方程,在lgσ-1000/T曲线上以为PEO的熔点为转折点,体现为两条斜率不同的直线,在80℃时体系的离子电导率为6.852×10-6 S/cm。红外光谱、XRD分析表明,加入SiO2后PEO的结晶度降低,体系不定形相增加,有利于离子电导率的提高。对该电解质薄膜进行了透光率测定,表明各组分下该薄膜透光率基本保持在96%以上,确定了将其应用于电致变色器件的可能性。     

Electrochemical synthesis of hydrogen peroxide: Rotating disk electrode and fuel cell studies

The electrochemical reduction of oxygen on various catalysts was studied using the thin-layer rotating disk electrode (RDE) method. High-surface-area carbon was modified with an anthraquinone derivative and gold nanoparticles. Polytetrafluoroethylene (PTFE) and cationic polyelectrolyte (FAA) were used as binders in the preparation of thin-film electrodes. Our primary goal was to find a good electrocatalyst for the two-electron reduction of oxygen to hydrogen peroxide. All electrochemical measurements were carried out in 0.1 M KOH. Cyclic voltammetry was used in order to characterise the surface processes of the modified electrodes in O₂-free electrolyte. The RDE results revealed that the carbon-supported gold nanoparticles are active catalysts for the four-electron reduction of oxygen in alkaline solution. Anthraquinone-modified high-area carbon catalyses the two-electron reduction at low overpotentials, which is advantageous for hydrogen peroxide production.In addition, the polymer electrolyte fuel cell technology was used for the generation of hydrogen peroxide. The cell was equipped with a bipolar membrane which consisted of commercial Nafion 117 as a cation-exchange layer and FT-FAA as an anion-exchange layer. The bipolar membranes were prepared by a hot pressing method. Use of the FAA ionomer as a binder for the anthraquinone-modified carbon catalyst resulted in production of hydrogen peroxide.     

SPE膜电极及其在化学传感器中的应用

Abstract The structure and proton conducting mechanism of solid polymer electrolyte (SPE) are described. Since the conductivity of electrolyte is important in SPE electrochemical cell research and development, we investigate quantitatively the conductivity of Nation membrane and its dependence on temperature and relative humidity. Experimental results show that the conductivity of Nation membrane increases with temperature and relative humidity.We also reports on the preparation and development of SPE membrane electrode with the emphasis on the mixture pressing method and impregnation-reduction process to prepare SPE composite electrode assemblies and their application to electrochemical sensors. We also investigate and fabricate a potentiometric electrochemical sensor of hydrogen and ethylene to measure the hydrogen and ethylene partial pressure.     

Performance of a direct methanol fuel cell

The performance of a direct methanol fuel cell based on a Nafion® solid polymer electrolyte membrane (SPE) is reported. The fuel cell utilizes a vaporized aqueous methanol fuel at a porous Pt–Ru–carbon catalyst anode. The effect of oxygen pressure, methanol/water vapour temperature and methanol concentration on the cell voltage and power output is described. A problem with the operation of the fuel cell with Nafion® proton conducting membranes is that of methanol crossover from the anode to the cathode through the polymer membrane. This causes a mixed potential at the cathode, can result in cathode flooding and represents a loss in fuel efficiency. To evaluate cell performance mathematical models are developed to predict the cell voltage, current density response of the fuel cell.     

Material aspects of the liquid feed direct methanol fuel cell

A study of a small scale Liquid Feed Direct Methanol Fuel Cell (LFDMFC), based on solid polymer electrolyte membrane, is reported. Two flow cell designs, one with a parallel flow channel arrangement and the other with a spot design of flow bed, are used. The structure of the DMFC comprises a composite of two porous electrocatalytic electrodes; Pt–Ru–carbon catalyst anode and Pt–carbon catalyst cathode, on either side of a solid polymer electrolyte (SPE) membrane. The performance of three Pt–Ru catalysts is compared. The influence of the degree of Teflon loading on the electrode structure is also reported. The effect of the following parameters: cell temperature, oxygen gas or air pressure, methanol liquid flow rate and methanol concentration on the power performance is described.     

Plastic power sources

Lithium ion polymer batteries and laminated solid-state redox supercapacitors, formed by placing a highly conducting gel-type membrane electrolyte between a graphite film and a composite cathode film and between a poly(pyrrole)–poly(aniline) electrode combination, respectively, have been fabricated and tested. The preliminary results are encouraging in suggesting that these plastic power sources may be particularly advantageous for mobile electronic products and for zero emission electric vehicles.