锂离子电池用凝胶聚合物电解质研究进展

凝胶聚合物电解质既具有固态聚合物电解质良好的力学加工性能和安全性能,又具有传统液态电解质较高的室温离子电导率。但凝胶聚合物电解质由于室温离子电导率低、力学强度较差的缺点限制了其在锂离子电池上的应用。结合目前研究的最新进展,本文针对几种常用凝胶聚合物电解质体系聚氧化乙烯、聚丙烯腈、聚甲基丙烯酸甲酯、聚偏氟乙烯-六氟丙烯和聚乙烯醇缩醛进行了综述,对其制备方法以及通过聚合物调控、加入无机填料和复合离子液体进行改性处理做了较全面的介绍,并探讨了凝胶聚合物电解质的应用前景。     

锂离子电池用固体聚合物电解质的最新进展

全固态聚合物电解质由于其突出的安全性能,在锂离子电池中具有潜在的应用前景,其研究备受关注.本文综述了锂离子电池用全固态聚合物电解质的最新研究进展.主要关注的是电化学性能,尤其是室温附近的离子电导率.对性能较好的聚合物固体电解质体系进行了概述.     

聚合物复合固体电解质材料研究进展

固体电解质是发展高安全、高能量密度全固态锂电池的重要材料基础。由聚合物相与无机相复合形成的聚合物复合固体电解质,兼具聚合物轻质、柔性,以及无机材料高强度、高稳定性等优势,是最具应用潜力的固体电解质材料。目前,制约聚合物复合固体电解质实际应用的主要瓶颈问题为其室温离子电导率较低。综述了目前关于聚合物复合固体电解质离子传导机制的科学认识以及提升其离子电导率的方法,分析了先进表征工具在揭示聚合物复合固体电解质离子传导机制方面的应用潜力,并展望了聚合物复合固体电解质未来的发展方向和工作重点。     

聚氧化乙烯-聚硅氧烷基离子液体复合聚合物电解质的研究

通过对不同聚硅氧烷(PDMS)含量的聚氧化乙烯-聚硅氧烷(PEO-PDMS)聚合物电解质电化学性能的测试,确定出PDMS最佳添加量,并以此聚合物配比为基体,通过复合不同质量分数的离子液体1-丁基-3-甲基咪唑双三氟甲磺酰亚胺盐([BMIM]TF-SI)或N-甲基、丙基哌啶双三氟甲磺酰亚胺盐(PP13TFSI),制备得到不同体系的离子液体复合聚合物电解质膜。离子液体的加入可显著提高聚合物电解质的室温电导率,样品PPP-100%室温电导率达到5.6×10-4S/cm。同时,样品均具有良好的热学和电化学稳定性。通过两种体系聚合物电解质性能对比得知,PP13TFSI离子液体复合聚合物电解质具有更优性能,有望作为新型电解质材料应用在锂离子电池中。     

PVDF-HFP基聚合物电解质膜的制备及性能表征

采用相转化法制备了PVDF-HFP基多孔聚合物电解质,研究了PVDF-HFP的溶解温度、溶剂用量以及非溶剂用量等因素对聚合物电解质性能的影响,分别采用交流阻抗法和稳态电流法测定了聚合物电解质膜的离子电导率和离子迁移数,并通过扫描电镜观察了多孔聚合物膜的表面形貌.研究表明,制备PVDF-HFP多孔聚合物电解质膜的合适条件为:溶胶温度50~60℃、溶胶时间2 h、溶剂与PVDF的质量比为9~11、非溶剂与PVDF的质量比为0.5~0.25.该条件下制得的多孔聚合物电解质膜的孔隙率达到70%左右、离子迁移数在0.3左右、室温离子电导率达到1.6×10-3S.cm-1.     

阳离子超支化聚合物电解质的合成及离子传导性能研究

以间苯三酚、1,2,4-偏苯三酸酐和环氧氯丙烷为原料合成不同支化度的超支化聚合物(HBP),利用合成的超支化聚合物外围的氯原子与N-甲基咪唑进行离子化反应,制备含咪唑阳离子的超支化聚合物电解质(HBPE)。利用1H-NMR、FT-IR、DSC、TG和复阻抗谱分析等对HBPE的化学结构,热力学性能和离子传导性能进行了研究,结果表明,该聚合物电解质室温离子电导率可达2.3×10-4S/cm,热稳定性在270℃以上。     

用于镍氢电池的PVA/PAAK碱性聚合物电解质的制备及性能

通过溶液浇铸和碱液活化的简易方法制备了聚乙烯醇(PVA)/聚丙烯酸钾(PAAK)碱性聚合物电解质。运用交流阻抗法、循环伏安(CV)和X射线衍射(XRD)等技术对碱性聚合物电解质进行表征,分析了PAAK对聚合物电解质离子电导率的影响。结果表明,PAAK对聚合物电解质导电性的作用主要表现在:一是使聚合物电解质中容纳更多的KOH溶液;二是能降低PVA的结晶度,从而提高聚合物电解质的离子电导率。所制备的PVA/PAAK碱性聚合物电解质最大室温电导率达3.074×10-2S/cm,电化学稳定窗口为2.2 V。以其实验室制备的镁基储氢合金为负极,组装的聚合物镍氢电池(MH-Ni电池)的循环寿命较传统的MH-Ni电池明显改善。     

PVA-KOH-H_2O碱性凝胶聚合物电解质的制备与表征

应用溶解-铸膜法制备聚乙烯醇(PVA)-KOH-H2O碱性凝胶聚合物电解质膜。用交流阻抗测试电解质膜离子电导率,结果表明随KOH含量增加,电解质膜的电导率先增后减,当m(PVA):m(KOH)=3:4.5时(质量比,下同),室温电导率达到最大值,为4.63×10-2S/cm。聚合物电解质膜的电导率随温度的变化基本符合Arrhenius方程。加入KOH后,PVA结构从晶态向非晶态转变,结晶度降低,热稳定性提高。循环伏安和DSC热分析显示该聚合物电解质膜具有很好的电化学稳定性和热稳定性。有望应用于碱性二次电池。     

侧链枝化的磷酸酯型聚合物电解质的合成与性能研究

以聚乙二醇200、二乙二醇单甲醚等与三氯氧磷反应制备得到枝化结构的磷酸酯单体,其末端为丙烯酸酯基团。紫外引发聚合制备聚合物电解质,考察了磷酸酯单体的分子量、温度、盐浓度对聚合物电解质电导率的影响。研究表明,在测试盐浓度下,复合体系的最大室温电导率对应的LiClO4盐浓度都为5%,PEP200_3与LiClO4复合后室温电导率最高,可达1.80×10-5S/cm。     

锂离子二次电池用全固态聚合物电解质的研究进展

对固体聚合物电解质的发展历程以及对全固态聚合物电解质中的离子传导作了介绍,着重对提高室温电导率的途径进行评述,并结合自己的工作对其存在的问题和今后的发展作出展望.     

聚(丙烯酸-丙烯酰胺)-碱金属盐复合物的离子电导性

聚（丙烯酸－丙烯酰胺）－碱金属盐复合物是一种新型高分子固体电解质。文中详细讨论了离子种类，盐浓度，增塑剂种类和用量以及温度等因素对其电导率的影响。结果表明，不同碱金属盐对电解质电导率的影响因其阳离子半径，晶格能，离子淌度以及在电解质中的溶解度的不同而不同。     

High ion conducting polymer nanocomposite electrolytes using hybrid nanofillers

There is a growing shift from liquid electrolytes toward solid polymer electrolytes, in energy storage devices, due to the many advantages of the latter such as enhanced safety, flexibility, and manufacturability. The main issue with polymer electrolytes is their lower ionic conductivity compared to that of liquid electrolytes. Nanoscale fillers such as silica and alumina nanoparticles are known to enhance the ionic conductivity of polymer electrolytes. Although carbon nanotubes have been used as fillers for polymers in various applications, they have not yet been used in polymer electrolytes as they are conductive and can pose the risk of electrical shorting. In this study, we show that nanotubes can be packaged within insulating clay layers to form effective 3D nanofillers. We show that such hybrid nanofillers increase the lithium ion conductivity of PEO electrolyte by almost 2 orders of magnitude. Furthermore, significant improvement in mechanical properties were observed where only 5 wt % addition of the filler led to 160% increase in the tensile strength of the polymer. This new approach of embedding conducting-insulating hybrid nanofillers could lead to the development of a new generation of polymer nanocomposite electrolytes with high ion conductivity and improved mechanical properties.     

Borohydride‐Scaffolded Li/Na/Mg Fast Ionic Conductors for Promising Solid‐State Electrolytes

Borohydride solid‐state electrolytes with room‐temperature ionic conductivity up to ≈70 mS cm^?1 have achieved impressive progress and quickly taken their place among the superionic conductive solid‐state electrolytes. Here, the focus is on state‐of‐the‐art developments in borohydride solid‐state electrolytes, including their competitive ionic‐conductive performance, current limitations for practical applications in solid‐state batteries, and the strategies to address their problems. To open, fast Li/Na/Mg ionic conductivity in electrolytes with BH₄ ^? groups, approaches to engineering borohydrides with enhanced ionic conductivity, and later on the superionic conductivity of polyhedral borohydrides, their correlated conductive kinetics/thermodynamics, and the theoretically predicted high conductive derivatives are discussed. Furthermore, the validity of borohydride pairing with coated oxides, sulfur, organic electrodes, MgH₂, TiS₂, Li₄Ti₅O₁₂, electrode materials, etc., is surveyed in solid‐state batteries. From the viewpoint of compatible cathodes, the stable electrochemical windows of borohydride solid‐state electrolytes, the electrode/electrolyte interface behavior and battery device design, and the performance optimization of borohydride‐based solid‐state batteries are also discussed in detail. A comprehensive coverage of emerging trends in borohydride solid‐state electrolytes is provided and future maps to promote better performance of borohydride SSEs are sketched out, which will pave the way for their further development in the field of energy storage.     

磷灰石类新型电解质材料研究进展

近年来,具有低活化能和高氧离子电导率的磷灰石类氧化物,作为中低温固体氧化物燃料电池中极具应用潜力的新型电解质材料受到了人们的广泛关注.本文介绍了磷灰石类氧化物的基本性质与其结构的关系,概述了掺杂对材料性能的影响,并讨论了存在的主要问题以及今后的发展趋势.     

锂离子电池玻璃态电解质导电机理的研究进展

锂离子电池玻璃态电解质同晶体型电解质相比较具有导电性各向同性、锂离子电导率高等诸多优点, 开发在室温下具有较高的离子电导率及良好的化学、电化学稳定性的玻璃态电解质材料已经成为锂离子电池领域的重要研究方向之一。本文介绍了各种玻璃态电解质体系的导电特性及导电机理, 并重点分析与讨论混合网络形成体效应在一些典型玻璃态电解质体系中的微观作用机理。本文还总结了混合网络形成体效应在玻璃态电解质中发生的前提条件, 并指出深入研究玻璃态电解质的导电机理对开发出具有优异电化学性能的无机非晶固态电解质体系具有重要的指导意义。     

Interfacial Interaction of Multifunctional GQDs Reinforcing Polymer Electrolytes For All-Solid-State Li Battery

Solid-state polymer electrolytes are highly anticipated for next generation lithium ion batteries with enhanced safety and energy density. However, a major disadvantage of polymer electrolytes is their low ionic conductivity at room temperature. In order to enhance the ionic conductivity, here, graphene quantum dots (GQDs) are employed to improve the poly (ethylene oxide) (PEO) based electrolyte. Owing to the increased amorphous areas of PEO and mobility of Li⁺, GQDs modified composite polymer electrolytes achieved high ionic conductivity and favorable lithium ion transference numbers. Significantly, the abundant hydroxyl groups and amino groups originated from GQDs can serve as Lewis base sites and interact with lithium ions, thus promoting the dissociation of lithium salts and providing more ion pathways. Moreover, lithium dendrite is suppressed, associated with high transference number, enhanced mechanical properties and steady interface stability. It is further observed that all solid-state lithium batteries assembled with GQDs modified composite polymer electrolytes display excellent rate performance and cycling stability.     

Highly conductive non aqueous polymer gel electrolytes containing ammonium hexafluorophosphate (NH4PF6)

Non aqueous polymer gel electrolytes based on polyethylene oxide (PEO) and ammonium hexafluorophosphate (NH₄PF₆) show high conductivity above 10⁻² S/cm at 25°C. The addition of PEO to liquid electrolytes has been found to result in an increase in free ion concentration by dissociating ion aggregates present in these electrolytes at higher concentrations (≥0.4 M) of NH₄PF₆ alongwith an increase in viscosity. The free ion concentration and viscosity play a dominant role on the conductivity behaviour of these polymer gel electrolytes at low and high concentrations of PEO respectively. The presence of ion aggregates and their dissociation with the addition of PEO has also been checked by FTIR and the results are in agreement with the conductivity behaviour.     

Conductivity behaviour of polymer gel electrolytes: Role of polymer

Polymer is an important constituent of polymer gel electrolytes along with salt and solvent. The salt provides ions for conduction and the solvent helps in the dissolution of the salt and also provides the medium for ion conduction. Although the polymer added provides mechanical stability to the electrolytes yet its effect on the conductivity behaviour of gel electrolytes as well as the interaction of polymer with salt and solvent has not been conclusively established. The conductivity of lithium ion conducting polymer gel electrolytes decreases with the addition of polymer whereas in the case of proton conducting polymer gel electrolytes an increase in conductivity has been observed with polymer addition. This has been explained to be due to the role of polymer in increasing viscosity and carrier concentration in these gel electrolytes.     

Electrochemical properties of composite electrolytes based on poly(ethylene oxide)/poly(ethylene imine) containing the inorganic silica fillers

In this study, poly(ethylene oxide) (PEO) and poly(ethylene imine) (PEI) polymer blends containing inorganic silica fillers were studied in order to enhance the ion conductivity and interfacial properties. Lithium perchlorate (LiCIO4) as a salt, and silica (SiO2) as the inorganic filler were introduced in the polymer electrolyte composites and were examined to evaluate their use to improve the ionic conductivity. The addition of inorganic fillers in polymer electrolytes has resulted in high ionic conductivity at a room temperature. The structure and morphology of the solid polymer electrolytes were evaluated using X-ray diffraction (XRD) and scanning electron microscope (SEM). The ionic conductivity was measured by an AC impedance method. The enhanced conductivity was dependent on the decreased crystallinity and more heterogeneous morphologies.     

Effect of plasticizer and fumed silica on ionic conductivity behaviour of proton conducting polymer electrolytes containing HPF6

The effect of addition of propylene carbonate (PC) and nano-sized fumed silica on the ionic conductivity behaviour of proton conducting polymer electrolytes containing different concentrations of hexafluorophosphoric acid (HPF₆) in polyethylene oxide (PEO) has been studied. The addition of PC results in an increase in ionic conductivity, whereas the addition of nano-sized fumed silica improves mechanical strength of electrolytes along with a small increase in ionic conductivity. It was observed that the simultaneous addition of PC and fumed silica results in electrolytes with optimum value of ionic conductivity and other properties.