PEO在聚合物锂离子电池中的应用

聚氧化乙烯（PEO）可与锂盐形成具有离子导电性的络合物，但PEO的高结晶性使其与锂盐构成的固体电解质在室温下电导率很低，不能满足实际应用要求，因此需对PEO基固体电解质进行改性。简介PEO的特点和离子传导机理，重点介绍提高PEO基固体电解质室温导电性能目前所采取的措施，包括形成共聚物、生成交联聚合物、掺杂复合物盐、加入增塑剂、加入无机填料和制备侧链含PEO链段高聚物。     

凝胶聚合物电解质的研究进展

介绍了几种聚合物高分子材料,常以其作为凝胶聚合物电解质基体。如聚氧化乙烯(PEO)、聚丙烯腈(PAN)、聚甲基丙烯酸甲酯(PMMA)、聚偏氟乙烯(PVDF)。对于凝胶聚合物电解质的研究,目前仍处于初级阶段,还存在许多问题。本文探讨了凝胶聚合物电解质的改性方法,主要有交联、共聚、共混或添加填料等,并展望了凝胶聚合物电解质的应用前景。     

增塑剂PC掺杂（PEO）_8-LiClO_4-SiO_2电解质体系的性能研究

以增塑剂碳酸丙烯酯（PC）作为掺杂物,混于（PEO）8-LiClO4-SiO2固体电解质体系中。得到厚度约为350μm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XRD对聚合物电解质薄膜的物相结构进行分析研究。结果表明掺杂后（PEO）8-LiClO4-SiO2-PC固体电解质的室温电导率较（PEO）8-LiClO4-SiO2体系有了进一步提高,在PC质量分数为40%时最高,达到3.083×10-6 S.cm-1;电导率与温度关系遵循Arrhenius方程。温度的升高有利于电导率的提升,在80℃时体系的离子电导率为1.180×10-5 S.cm-1。XRD分析表明,加入PC后PEO的结晶度进一步减小,体系不定形相增加,有利于离子电导率的提高。     

快冷对PEO/LiClO_4固态电解质的晶型与导电性的影响

聚合物电解质的离子电导率是电解质的一个重要参数 ,与聚合物电解质中的非晶态的存在有很大的关系。在本文中 ,以X射线衍射 (XRD)、差热分析 (DTA)和交流阻抗 (Acimpedance)为研究手段 ,研究了快冷对聚合物电解质的晶型转变和对聚合物电解质室温离子电导率的影响。在快速冷却的条件下 ,质量比为1∶1的PEO/LiClO4聚合物电解质的室温离子电导率可达 1 6 1x 10 -7S/cm ,比慢冷处理的相同体系的室温离子电导率提高了 1个数量级。实验证明 ,快速冷却可破坏聚合物的结晶性 ,提高聚合物电解质的离子电导率。     

聚合物基镁离子固态电解质的研究进展Q

镁离子电池因其比容量高、资源丰富、环境友好、安全性高(无枝晶)等优势,在储能电池领域脱颖而出.然而,镁金属负极在液态电解质中易钝化,导致其电化学性能不佳.因此,开发高效适用的固态电解质对实现高性能、实用化镁离子电池至关重要.聚合物电解质具有优异的机械稳定性、电化学稳定性、热稳定性且离子电导率高、成本低.但镁离子较高的电荷密度和较强的溶剂化作用限制了其在固态电解质中的解离与扩散.从纯固态聚合物电解质、凝胶聚合物电解质、复合聚合物电解质3个方面综述了国内外聚合物基镁离子固态电解质的离子电导率对解决镁金属负极钝化效应的贡献及其应用研究进展,指出聚合物基镁离子固态电解质当前面临的挑战并对其研究方向进行了建议和展望.     

PEO基聚合物电解质的研究进展

聚合物电解质是解决商业化锂离子电池安全性问题的一条有效途径。聚环氧乙烷类(PEO)具有良好的热稳定性和电化学稳定性,是一种有发展潜力的聚合物电解质骨架组分。介绍了PEO基聚合物电解质的导电机理,并对其在国内外的研究动态进行了综述,主要介绍了几种提高电导率的方法和新型PEO基电解质体系。最后对PEO基聚合物电解质的研究进行了展望。     

聚合物电解质的研究进展

介绍了锂离子电池的特点、市场前景及聚合物锂离子电池的种类,综述了聚合物电解质的发展历程,重点阐述了近来研究较多的几种聚合物电解质的研究进展,包括:聚偏氟乙烯基(PVDF基)、聚丙烯腈基(PAN基)、聚甲基丙烯酸甲酯基(PMMA基)和聚乙烯类(PE)聚合物电解质。     

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。     

聚氨酯基聚合物电解质的研究进展

聚合物锂离子电池因具有能量密度高、绿色环保等优点备受关注,聚合物电解质作为锂离子电池的重要组成部分,发展高效聚合物电解质成为研究热点。聚氨酯由不相容的软硬两段组成,结构可设计性强,硬段部分作为物理交联点提供机械强度和热稳定性,软段部分溶解碱金属盐提供离子导电性,因而聚氨酯是作为锂电池聚合物电解质的优良材料。通过改进聚氨酯基聚合物电解质的电化学性能和增加聚氨酯基聚合物电解质的功能性两个方面综述了国内聚醚型、聚酯型、有机硅氧烷改性、聚氧化乙烯改性、聚乳酸改性和功能型聚氨酯基电解质的研究进展,并展望了未来聚氨酯基聚合物电解质的发展前景。     

一种双离子梳状聚合物电解质的合成与性能研究

以端基含有烯丙基侧链含有氯甲基的不饱和聚醚 (UPEO)与苯乙烯 (St)共聚 ,得到以聚烯烃为主链、PEO为侧链、侧链挂载氯甲基的梳状聚合物 (CPPC) ,CPPC与亚硫酸锂反应 ,合成了一种新型单离子梳状聚合物电解质 (CPPL)。研究发现该梳状聚合物电解质的玻璃化温度 (θg)取决于苯乙烯的配比和磺化反应效率。对比研究了CPPL和CPPL复合LiClO4而成的双离子梳状聚合物电解质(CPPL2 )的θg、热稳定性、电化学窗口和电导率。测定结果表明 :CPPL和CPPL2的室温电导率分别为1.3× 10 -4s/cm和 7.8× 10 -4s/cm。     

Nuclear magnetic resonance study of PEO-chitosan based polymer electrolytes

This work investigates lithium dynamics in a series of polymer electrolytes formed by poly(ethylene oxide) PEO, chitosan (QO), amino propil siloxane (pAPS) and lithium perchlorate by means of nuclear magnetic resonance techniques. Lithium (⁷Li) lineshapes and spin-lattice relaxation times were measured as a function of temperature. The results suggest that the chemical functionality of QO, particularly the amine group, participate in coordinating lithium ion in the composites. The competition between QO and PEO for lithium ions is evident in the binary system. In the ternary electrolyte containing PEO, QO and pAPS, it is observed that the lithium ions can competively interact with the two polymers. The heterogeneity, at a local microscopic scale, is revealed by a temperature-dependent equilibrium of lithium ion concentration between at least two different microphases; one dominated by the interactions with chitosan and the other one with polyether. The data of the ternary electrolyte was analysed by assuming two lithium dynamics, the first one associated to the motion of the lithium ion dissolved in PEO and the second one associated to those complexed by the chitosan.     

Ionic conductivity and interfacial properties of polymer electrolytes based on PEO and boroxine ring polymer

Blended polymer electrolytes based on poly(ethylene oxide) (PEO) and boroxine ring polymer (BP) solvated with lithium triflate were formulated and evaluated. Compared to PEO–salt polymer electrolyte, ionic conductivities of blended polymer electrolytes were two orders of magnitude higher in a low‐temperature range; as well, lithium transference numbers were increased to ～ 0.4. These were due to the increased mobility and anion trapping of boroxine rings. BP also exhibited the stabilizing effect on lithium–polymer electrolyte interface, and a reduced interfacial resistance between lithium metal and the polymer electrolyte was found with increasing of BP content. Polymer electrolytes based on PEO and BP are suitable for use in lithium secondary battery. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 17–21, 2002; DOI 10.1002/app.10090     

Novel composite polymer electrolyte comprising poly(ethylene oxide) and triblock copolymer/mesostructured silica hybrid used for lithium polymer battery

Ordered mesoporous materials, due to its potential applications in catalysis, separation technologies, and nano-science have attracted much attention in the past few years. In this work, a novel PEO-based composite polymer electrolyte by using organic-inorganic hybrid EO₂₀PO₇₀EO₂₀ @ mesoporous silica (P123 @ SBA-15) as the filler has been developed. The interactions between P123 @ SBA-15 hybrid and PEO chains are studied by X-ray diffraction (XRD), differential scanning calorimeter (DSC), and FT-IR techniques. The effects of P123 @ SBA-15 on the electrochemical properties of the PEO-based electrolyte, such as ionic conductivity, lithium ion transference number are studied by electrochemical ac impedance spectroscopy and steady-state current method. The experiment results show that P123 @ SBA-15 can enhance the ionic conductivity and increase the lithium ion transference number of PEO-based electrolyte, which are induced by the special topology structure of P123 in P123 @ SBA-15 hybrid, at the same time. The excellent lithium transport properties and broad electrochemical stability window suggesting that PEO-LiClO₄/P123 @ SBA-15 composite polymer electrolyte can be used as candidate electrolyte materials for lithium polymer batteries.     

New solid polymer electrolytes based on PEO/PAN hybrids

Hybrid polymer dry electrolytes comprised of poly(ethylene oxide) (PEO), polyacrylonitrile (PAN), and LiClO₄ were investigated. The impedance spectroscopy showed that the effect of PAN on the ion conductivity of PEO‐based electrolytes depends on the concentration of lithium salt. When the mole ratio of lithium to oxygen is 0.062 (15%LiClO₄‐PEO), adding PAN will increase the ionic conductivity. Differential scanning calorimetry, NMR, and IR data suggested that the enhanced conductivity was due to both the decreasing of the PEO crystallinity and increasing of the degree of ionization of lithium salt. There was obviously no interaction between PAN and lithium ions, and PAN acts as a reinforcing filler, and hence contributes to the mechanical strength besides reducing the crystallinity of the polymer electrolytes. When the LiClO₄‐PEO‐PAN hybrid polymer electrolyte was heated at 200°C under N₂, PAN crosslinked partially, which further decreased the crystallinity of PEO and increased the ionic conductivity, and at the same time prevented the recrystallization of PEO upon sitting at ambient environment. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1530–1540, 2006     

Morphology and electrochemical and mechanical properties of polyethylene‐oxide‐based nanofibrous electrolytes applicable in lithium ion batteries

We report the synthesis of all‐solid‐state polymeric electrolytes based on electrospun nanofibers. These nanofibers are composed of polyethylene oxide (PEO) as the matrix, lithium perchlorate (LiClO₄) as the lithium salt and propylene carbonate (PC) as the plasticizer. The effects of the PEO, LiClO₄ and PC ratios on the morphological, mechanical and electrochemical characteristics were investigated using the response surface method (RSM) and analysis of variance test. The prepared nanofibrous electrolytes were characterized using SEM, Fourier transform infrared, XRD and DSC analyses. Conductivity measurements and tensile tests were conducted on the prepared electrolytes. The results show that the average diameter of the nanofibers decreased on reduction of the PEO concentration and addition of PC and LiClO₄. Fourier transport infrared analysis confirmed the complexation between PEO and the additives. The highest conductivity was 0.05 mS cm^?1 at room temperature for the nanofibrous electrolyte with the lowest PEO concentration and the highest ratio of LiClO₄. The optimum nanofibrous electrolyte showed stable cycling over 30 cycles. The conductivity of a polymer film electrolyte was 29 times lower than that of the prepared nanofibrous electrolyte with similar chemical composition. Furthermore, significant fading in mechanical properties was observed on addition of the PC plasticizer. The results obtained imply that further optimization might lead to practical uses of nanofibrous electrolytes in lithium ion batteries. © 2019 Society of Chemical Industry     

Polymer chain organization in tensile-stretched poly(ethylene oxide)-based polymer electrolytes

Polymer chain orientation in tensile-stretched poly(ethylene oxide)-lithium trifluoromethanesulfonate polymer electrolytes are investigated with polarized infrared spectroscopy as a function of the degree of strain and salt composition (ether oxygen atom to lithium ion ratios of 20:1, 15:1, and 10:1). The 1359 and 1352 cm(-1) bands are used to probe the crystalline PEO and P(EO)(3)LiCF(3)SO(3) domains, respectively, allowing a direct comparison of chain orientation for the two phases. Two-dimensional correlation FT-IR spectroscopy indicates that the two crystalline domains align at the same rate as the polymer electrolytes are stretched. Quantitative measurements of polymer chain orientation obtained through dichroic infrared spectroscopy show that chain orientation predominantly occurs between strain values of 150% and 250%, regardless of salt composition investigated. There are few changes in chain orientation for either phase when the films are further elongated to a strain of 300%; however, the PEO domains are slightly more oriented at the high strain values. The spectroscopic data are consistent with stretching-induced melt-recrystallization of the unoriented crystalline domains in the solution-cast polymer films. Stretching the films pulls polymer chains from the crystalline domains, which subsequently recrystallize with the polymer helices parallel to the stretch direction. If lithium ion conduction in crystalline polymer electrolytes is viewed as consisting of two major components (facile intra-chain lithium ion conduction and slow helix-to-helix inter-grain hopping), then alignment of the polymer helices will affect the ion conduction pathways for these materials by reducing the number of inter-grain hops required to migrate through the polymer electrolyte.     

Poly(ethylene oxide)‐based block copolymer electrolytes for lithium metal batteries

Nanostructured block copolymer electrolytes (BCEs) based on poly(ethylene oxide) (PEO) are considered as promising candidates for solid‐state electrolytes in high energy density lithium metal batteries (LMBs). Because of their self‐assembly properties, they confer on electrolytes both high mechanical strength and sufficient ionic conductivity, which linear PEO cannot provide. Two types of PEO‐based BCEs are commonly known. There are the traditional ones, also called dual‐ion conducting BCEs, which are a mixture of block copolymer chains and lithium salts. In these systems, the cations and anions participate in the conduction, inducing a concentration polarization in the electrolyte, thus leading to poor performances of LMBs. The second family of BCEs are single‐lithium‐ion conducting BCEs (SIC‐BCEs), which consist of anions being covalently grafted to the polymer backbone, therefore involving conduction by lithium ions only. SIC‐BCEs have marked advantages over dual‐ion conducting BCEs due to a high lithium ion transference number, absence of anion concentration gradients as well as low rate of lithium dendrite growth. This review focuses on the recent developments in BCEs for applications in LMBs with particular emphasis on the physicochemical and electrochemical properties of these materials. © 2018 Society of Chemical Industry     

An all solid-state polymer—polymer electrolyte—lithium rechargeable battery for room temperature applications

A new polymer electrolyte based on polyethylene oxide (PEO) and styrenic macromonomer of PEO—lithium perchlorate complexes, conceived for room-temperature battery applications, has been tested in a lithium polybithiophene rechargeable battery. Cyclability and stability data are reported and discussed.     

Effect of additives in PEO/PAA/PMAA composite solid polymer electrolytes on the ionic conductivity and Li ion battery performance

Polyethylene oxide (PEO) based-solid polymer electrolytes were prepared with low weight polymers bearing carboxylic acid groups added onto the polymer backbone, and the variation of the conductivity and performance of the resulting Li ion battery system was examined. The composite solid polymer electrolytes (CSPEs) were composed of PEO, LiClO_4, PAA (polyacrylic acid), PMAA (polymethacrylic acid), and Al₂O₃. The addition of additives to the PEO matrix enhanced the ionic conductivities of the electrolyte. The composite electrolyte composed of PEO:LiClO₄:PAA/PMAA/Li_0.3 exhibited a low polarization resistance of 881.5 ohms in its impedance spectra, while the PEO:LiClO₄ film showed a high value of 4,592 ohms. The highest ionic conductivity of 9.87 × 10⁻⁴ S cm⁻¹ was attained for the electrolyte composed of PEO:LiClO₄:PAA/PMAA/Li_0.3 at 20 °C. The cyclic voltammogram of Li⁺ recorded for the cell consisting of the PEO:LiClO₄:PAA/PMAA/Li_0.3:Al₂O₃ composite electrolyte exhibited the same diffusion process as that obtained with an ultra-microelectrode. Based on this electrolyte, the applicability of the solid polymer electrolytes to lithium batteries was examined for an Li/SPE/LiNi_0.5Co_0.5O₂ cell.