螺旋纳米炭纤维的制备及其电化学性能

以乙炔为碳源,酒石酸铜为催化剂前躯体,氩气为保护气体,采用化学气相沉积法制备螺旋纳米炭纤维,通过扫描电镜观察不同温度下制备的螺旋纳米炭纤维的形貌;制备的螺旋纳米炭纤维作为锂离子电池负极材料,通过首次充放电、循环伏安、循环性能和交流阻抗谱测试电池的电化学性能。研究表明:在580℃下制备的螺旋纳米炭纤维管径均匀、螺旋化程度高,组装的电池具有最长的充放电平台,50次充放电循环后,库伦效率能保持在98.0%以上,比容量也保持在400 mA·h/g以上,循环伏安曲线重合性好,说明电化学性能稳定,电化学阻抗最小,导电性最好。螺旋纳米炭纤维纯度越高具有更好的电化学性能。     

锂氧电池LATP固态电解质的制备及性能

采用Pechini法制备了钠超离子导体(NASCION)型Li1.4Al0.4Ti1.6(PO4)3(LATP)固态电解质,并将其应用于锂氧电池。通过XRD以及SEM表征了LATP的结构及形貌。结果显示:所制备的LATP电解质晶粒粒径均匀,致密度高。使用电化学阻抗谱评价了LATP固态电解质的离子电导率,并通过充放电测试考察了使用固态电解质的锂氧电池的充放电性能。结果表明:所制备的LATP具有较高的锂离子电导率,30℃时LATP的离子电导率为1.1×10–4 S/cm;LATP可以有效地降低锂氧电池在放电及充电过程中的副反应,提高锂氧电池的充放电循环性能。     

添加TiO2的聚合物电解质膜PVDF-HFP的性能研究

通过添加不同质量分数的TiO2纳米粒子制备多孔聚合物电解质膜PVDF-HFP,制备的聚合物电解质膜通过红外,交流阻抗,线性伏安扫描、首次充放电测试等方法进行了性能测试。添加TiO2纳米填料后,降低了聚合物链的结晶度和极性,当填料的质量分数为8%时,表现出较好的电化学性能,吸液率为184%,孔隙率为93%,室温电导率达到2.05×10-3 S/cm,电化学稳定窗口为4.7V,能满足要求。     

蚕丝/聚氧化乙烯复合固态聚合物电解质

以天然蚕丝为骨架支撑材料,将聚氧化乙烯(PEO)和锂盐溶液浇铸在蚕丝上干燥成膜,制备得到蚕丝/PEO复合固态聚合物电解质(Silk-PEO-SPE)。通过FTIR、电子拉力机、同步热分析仪、电化学窗口测试、电导率测试对固态聚合物电解质进行了结构和性能表征,并以磷酸铁锂为正极,金属锂为负极组装全固态电池,测试了电池的充放电性能。结果表明,与传统PEO固态聚合物电解质相比,复合固态聚合物具有较好的机械强度(达到10 MPa)和优异的电化学窗口(达到4.6 V),以该电解质组装的全固态锂电池在60℃、1 C电流密度下放电比容量达到113 mA·h/g,循环100次容量保持率达到97%,显示出较优异的循环稳定性。     

丁二腈作为电解液添加剂的研究

在1 mol/L 六氟磷酸锂/［碳酸乙烯酯（EC）+碳酸二甲酯（DMC）+碳酸甲乙酯（EMC）（体积比为1∶1∶1）］的电解液中加入添加剂丁二腈（SN）,用循环伏安（CV）、恒流充放电、电化学阻抗谱（EIS）等方法,研究了丁二腈对电解液的电化学窗口、电池的比容量、电池的首次充放电效率和电池的循环性能的影响。结果表明,在电解液中加入一定量的高纯度丁二腈,能提高电池的比容量、首次充放电效率和拓宽电解液的电化学稳定窗口,从而提高电解液的热稳定性,改善电解液的循环性能。     

凝胶聚合物电解质的电化学性能

用化学交联法制备了凝胶聚合物电解质.聚烯烃多孔膜支撑的凝胶聚合物电解质具有优良的电化学性能, 室温电导率为1.01×10^-3S•cm^-1,锂离子迁移数为0.41,在Al电极上的氧化起始电位达到4.2 V以上.采用聚烯烃多孔膜支撑的凝胶聚合物电解质制备了聚合物锂离子电池,并研究了工艺条件对聚合物锂离子电池电化学性能的影响.研究的工艺条件包括：单体添加量和电极组合方式.优化后的聚合物锂离子电池具有良好的电化学性能,1 C放电容量为0.2 C放电容量的93.2%,经100次1 C循环后的剩余容量仍在80%以上.     

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。     

一种新型聚合物电解质中离子传递及界面性质研究

合成了聚（甲基丙烯酸甲酯-丙烯腈-甲基丙烯酸锂）（简记为PMAML）聚合物基质材料，以PMAML和聚偏氟 乙烯混合物为基质制备了新型复合聚合物电解质，其中增塑剂为碳酸乙烯酯和碳酸二甲酯，锂盐是LiBF4。用刮刀 在玻璃板上涂膜得到取合物膜，把聚合物基质膜在电解质溶液中浸渍后成为聚合物电解质膜。采用限制扩散方法测 试了电解质中离子的扩散系数，由稳态极化法测得了迁移数。所制聚合物电解质中锂离子的扩散系数和迁移数分别为 2.67×10-7cm2·s-1和0.53。通过交流阻抗技术研究了聚合物电解质与电极间界面性质，Li/GPE/Li的界面阻抗随放置 时间延长而增大，Li/GPE/MPCF的界面阻抗随电极的电位降低而减小。组装了聚合物电解质锂离子电池，测试结果表 明，该聚合物电解质具有较好的离子传输性质和电化学性能，能用作锂离子电池的电解质。     

一种嵌段星形凝胶聚合物电解质的制备与性能

将二-乙二醇甲基丙烯酸酯嵌入多羟基醇的烯酸酯中,制备嵌段星形凝胶聚合物电解质,用循环伏安、交流阻抗、X射线衍射等研究电解质和聚合物电池的性质。结果表明,二-乙二醇甲基丙烯酸酯的嵌入可明显改善凝胶的性能,获得的电解质黏性好,室温电导率为1.89mS/cm,单体用量少;以此制备的聚合物电池界面阻抗为110Ω,50次循环后容量保持率达到96%,倍率放电能力优良。二-乙二醇甲基丙烯酸酯的嵌入扩展了聚合物链间的空间,降低了分子的规整性,减小了离子迁移活化能。     

氟代碳酸乙烯酯用作电解液添加剂的研究

在1 mol.L-1LiPF6碳酸乙烯酯(EC)+碳酸二甲酯(DMC)+碳酸甲乙酯(EMC)(EC、DMC、EMC体积比为1∶1∶1)的电解液中加入添加剂氟代碳酸乙烯酯(FEC),用循环伏安(CV)、恒流充放电、电化学阻抗谱(EIS)等方法,研究了FEC对电解液的电化学窗口、LiNi0.5Mn1.5O4/Li和Li/MCMB半电池的性能影响。结果表明,在电解液中添加10%的FEC,可以拓宽电解液的电化学窗口,能在MCMB表面形成稳定的固体电解质相界面(SEI)膜,在室温1 C倍率下,LiNi0.5Mn1.5O4/Li电池循环50次后容量保持率能达到97.31%。     

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.     

Novel polymeric systems for lithium-ion batteries gel electrolytes: I. Cross-linked polyfluorosilicone

The investigation of chemically cross-linked, self-supporting gel-type electrolyte membranes, based on hybrid polyfluorosilicone polymers reinforced with nanosized silica, for lithium-ion battery systems is reported. The polyfluorosilicone materials were selected on the basis of their high chemical and thermal stabilities. The precursors were synthesized with functional groups capable to form inter-molecular cross-linking, thus obtaining three-dimensional polymer matrices. The latter were undergone to swelling processes in (non-aqueous, lithium salt containing) electrolytic solutions to obtain gel-type polymer electrolytes. Several kinds of membranes, based on different types of polyfluorosilicone precursor, were prepared and characterized in terms of swelling behavior, ionic conductivity and electrochemical stability. The properties of the swelled matrices were evaluated as a function of dipping time, temperature, kind of electrolytic solution and cross-linking initiator content.     

Proton-conducting polymer electrolyte membranes based on hydrocarbon polymers

This paper presents an overview of the synthesis, chemical and electrochemical properties, and polymer electrolyte fuel cell applications of new proton-conducting polymer electrolyte membranes based on hydrocarbon polymers. Due to their chemical stability, high degree of proton conductivity, and remarkable mechanical properties, perfluorinated polymer electrolytes such as Nafion^®, Aciplex^®, Flemion^®, and Dow membranes are some of the most promising electrolyte membranes for polymer electrolyte fuel cells. A number of reviews on the synthesis, electrochemical properties, and fuel cell applications of perfluorinated polymer electrolytes have also appeared during this period. While perfluorinated polymer electrolytes have satisfactory properties for a successful fuel cell electrolyte membrane, the major drawbacks to large-scale commercial use involve cost and low proton-conductivities at high temperatures and low humidities. Presently, one of the most promising ways to obtain high performance proton-conducting polymer electrolyte membranes is the use of hydrocarbon polymers for the polymer backbone. The present review attempts for the first time to summarize the synthesis, chemical and electrochemical properties, and fuel cell applications of new proton-conducting polymer electrolytes based on hydrocarbon polymers that have been made during the past decade.     

Electrochemical characteristics of electric double layer capacitor using sulfonated polypropylene separator impregnated with polymer hydrogel electrolyte

Sulfonated polypropylene separators impregnated with the polymer hydrogel electrolyte were used in electric double layer capacitors (EDLCs). The electrochemical properties of the EDLC with the polymer hydrogel electrolyte were investigated by cyclic voltammetry and charge-discharge cycle tests and compared with a KOH aqueous electrolyte. Furthermore, effects of KOH concentration and temperature on capacitance of the EDLC were studied. As a result, it was found that the capacitance of the EDLC with the polymer hydrogel electrolyte was higher than that with a KOH aqueous solution in the wide range of KOH concentration and temperature.     

Electrochemical characterization of new electric double layer capacitor with polymer hydrogel electrolyte

A new electric double layer capacitor (EDLC) was constructed by using polymer hydrogel electrolyte prepared from crosslinked potassium poly(acrylate) and KOH aqueous solution, and its electrochemical characteristics were investigated by cyclic voltammetry and charge-discharge cycle tests, compared with a case of the cell using only a KOH aqueous solution as an electrolyte. As a result, the cell with the polymer hydrogel electrolyte was found to exhibit higher capacitance than that with the KOH aqueous solution and excellent high-rate dischargeability. The impedance spectroscopic measurements suggested that the higher capacitance could be ascribed to the pseudocapacitance. These results indicate the potential applicability of the polymer hydrogel electrolyte to EDLCs as an electrolyte with good performance.     

Gel polymer electrolyte with semi-IPN fabric for polymer lithium-ion battery

A new type of semi-IPN gel electrolyte was prepared by thermal polymerization in this article. At first, the crosslinkable PEG200 (MXPEG) was prepared by condensation reaction, then the crosslinkable components were blent with PMMA and heated under vacuum to form polymer blends with semi-IPN fabric. Differential scanning calorimetry and X-ray diffraction spectroscopy were used to investigate the thermal properties and crystalline/amorphous structure of the prepared polymer blends. With semi-IPN fabric, they present amorphous absolutely. For semi-IPN gel electrolyte, the mechanical and the electrochemical properties are varied with the quantity of absorbed liquid electrolyte. Ion-conductivity behavior for semi-IPN gel electrolyte measured by means of AC impedance spectrum showed that the best data was 1.62 × 10⁻³S cm⁻¹ at room temperature, and Arrhenius-type relationship was obeyed in the temperature dependence of ionic conductivity. In addition, the electrochemical stability window of the semi-IPN gel electrolyte was 4.6 V. All the properties showed that the prepared semi-IPN gel electrolyte was expected to have applications of electrolyte for lithium-ion polymer secondary batteries. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

A novel polymer electrolyte based on PMAML/PVDF-HFP blend

A gel polymer electrolyte based on the blend of poly(methyl methacrylate-co-acrylonitrile-co-lithium methacrylate) (PMAML) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) was prepared and characterized. The synthesized PMAML were characterized by FTIR and NMR, respectively, and the surface morphology of the PMAML and PVDF-HFP blend membrane was also observed by scanning electron microscope (SEM). The electrochemical properties of composite electrolyte membranes were studied. The ionic conductivity of the polymer electrolyte composed of 75 wt.% 1 M LiBF₄ in ethylene carbonate (EC) and dimethyl carbonate (DMC) (EC:DMC=1:1 by weight) was about 2.6×10⁻³ S cm⁻¹ at ambient temperature. The electrochemical window of the polymer electrolyte was about 4.6 V determined from the linear sweep voltammetry plot. The lithium ion polymer batteries were assembled by sandwiching gel polymer electrolyte between LiCoO₂ cathode and mesophase carbon fibre (MPCF) anode. Charge-discharge test results display that lithium ion batteries with these gel polymer electrolytes have good electrochemical performance.     

Preparation of alkaline PVA-based polymer electrolytes for Ni–MH and Zn–air batteries

Alkaline PVA polymer electrolyte with high ionic conductivity of about 0.047 S cm^–1 at room temperature was obtained by a solution casting method. The PVA polymer electrolytes, blended with KOH and H₂O, were studied by DSC, TGA, cyclic voltammetric and a.c. impedance methods. The PVA polymer electrolytes show good mechanical strength and high ionic conductivity. The electrochemical stability window at the metal–electrolyte interface is ±1.2 V for stainless steel. Ni–MH and Zn–air batteries with PVA polymer electrolytes were assembled and tested. Experimental results show good electrochemical performances of the PVA-based Ni–MH and Zn–air batteries.     

Preparation and electrochemical properties of nonwoven reinforced solid polymer electrolytes

Summary Reinforced PEO-based polymer electrolytes were prepared by UV curing method. In this study, nonwoven sheets which were polyethylene terephthalate and polypropylene were used for that purpose. To enhance the ionic conductivity of reinforced PEO-based polymer electrolytes, oligomeric poly(ethylene glycol) dimethyl ether was added as a plasticizer, which is a sort of nonvolatile chemicals. The reinforced PEO-based polymer electrolytes showed the ionic conductivity of around 1.2 × 10⁻⁴ S/cm at 30°C, which was a little bit lower than the value of not reinforced one, that is pristine UV cured SPE. Even though the reinforced PEO-based polymer electrolytes didn't have any organic solvent such as ethylene carbonate, lithium ionic type polymer cell containing the polymer electrolyte showed reasonable specific discharge capacity of 116 mAh/g at room temperature. Received: 25 February 2000/Accepted: 14 April 2000