准固态电解质在染料敏化太阳电池中的应用和发展

染料敏化太阳电池（DSCs,dye-sensitized solar cells）近年已经成为一个研究热点。而电解质对电池的效率和稳定性起着重要的作用。目前常用的乙腈基液态电解质存在封装和泄漏的问题,尤其是在高温下。将准固态聚合物电解质应用到 DSCs 中可以有效解决应用液态电解质遇到的封装难稳定性差等问题,因而近年来,对准固态电解质的研究引起了广泛关注。本文综述了准固态电解质的研究进展,根据固化方式的不同将准固态电解质分为：有机小分子凝胶电解质、聚合物凝胶电解质和添加纳米粒子的凝胶电解质;讨论了每种准固态电解质的特点及存在的问题;最后对准固态电解质的发展进行展望。     

准固态电解质的制备及在染料敏化太阳电池中的应用

以聚2-乙基-2-唑啉作为基体,1,4-丁内酯为有机溶剂制备准固态电解质并应用于染料敏化太阳电池(DSSC)。经过各个组成的优化,准固态电解质电导率(25℃)达到0.36mS·cm~(-1),DSSC的光电转换效率在100mW·cm~(-2)光强下达2.10%。通过在准固态电解质中加入添加剂4-叔丁基吡啶,DSSC的光电转换效率提高至2.57%。     

有机物辅助的硫化物电解质基固态电池

固态电池利用固态电解质替换电解液,为电池的发展提供了高能量密度和高安全性的保障,其中硫化物固态电解质因其高离子电导率等优势受到了广泛关注。然而使用硫化物固态电解质还会面临电极/电解质接触较差、与电极发生界面副反应、空气稳定性差的问题,往往需要与一些有机物配合以改善电池性能,例如有机溶剂、有机电解液或聚合物。本文综述了不同种类有机物对硫化物固态电解质的辅助作用,首先回顾了基于硫化物固态电解质的准固态电池发展现状,分别从正极、电解质、负极及相互界面处添加电解液或溶液的角度,阐述了液体添加对准固态电池产生的界面浸润、构筑保护层等增益作用;其次介绍了聚合物/硫化物复合固态电解质的湿法和干法制备,对比了极性和非极性聚合物黏结剂在制备工艺上的差异,着重分析了有机组分的添加对复合电解质离子电导率等性能的影响;阐述了通过溶液法对复合正极内部界面的改善方法,并补充介绍了薄片状(Sheet-type)电极的制备工艺与发展前景;最后总结了目前有机组分在与硫化物固态电解质配合时面临的难点,展望了未来研究工作的发展方向,为组装高性能硫化物基固态电池提供思路。     

固态锂电池研究及产业化进展

相比于传统液态锂离子电池,固态锂电池(SSLB)用固态电解质代替有机电解液,安全性和能量密度均大大提升,可以有效降低电动汽车安全隐患和缓解用户续航里程焦虑.固态电解质作为电子绝缘体和离子导体是SSLB核心要素之一,同时其存在离子电导率低、界面阻抗大和界面稳定性差等问题.通过研究近期相关文献,对硫化物固态电解质、氧化物固态电解质、聚合物固态电解质以及复合固态电解质锂电池的离子导电机理、研究进展、存在的主要问题及解决方案进行了综述和讨论.对于提高离子电导率,重点介绍了调整固态电解质组分的方法.对于改善界面问题,主要介绍了界面设计和制成工艺方法改善思路.综合分析表明,通过掺杂和包覆改性固态电解质、探索先进界面研究和诊断技术并指导设计具有优良锂离子传输能力的界面、创新和优化工艺能有效地提升固态电解质综合性能.最后列举了国内外重点企业的固态锂电池产业化进程,对固态锂电池未来应用前景进行了分析和展望.     

染料敏化太阳电池准固态电解质光电功能的优化分析

通过对准固态电解质的内部微观结构的分析,阐述准固态电解质的微观结构对其光电功能(光功能和电功能)特性的影响,及其对染料敏化太阳电池(DSSC)光伏性能的影响。研究表明:基于向列相液晶4-氰基-4'-庚氧基联苯的准固态电解质中,其三维网状结构的尺寸处于亚微米级,且网孔尺寸较大,具有较好的光散射功能并有利于离子的传输,能够显著提高DSSC中染料的光吸收,提高准固态DSSC的光电流密度。     

固态电池复合电解质研究综述

目前单一的无机固态电解质、聚合物固态电解质分别存在着离子电导率低、产生枝晶、界面不稳定等各种问题,无法满足全固态锂金属电池的性能要求.有机聚合物电解质和无机电解质复合形成的复合固态电解质能够不同程度地增强电导率、抑制枝晶产生、提高机械强度、提高界面稳定性以及兼容性等,得到了广泛关注与研究.本文综述了复合固态电解质在提高锂离子电导率、抑制锂枝晶、提高电化学稳定性三个重要方面的改进方向、措施,并展望复合固态电池的发展方向,为复合固态电池的发展和应用提供借鉴.     

有机无机复合锂离子电池固态电解质专利分析

随着新能源汽车产业的飞速发展,传统液态电解质已经不能满足市场需求,固态电解质因其安全和能量密度优势已经成为未来发展的理想方向。然而由于无机电解质界面性能差和聚合物电解质材料离子电导率低的固有缺陷,严重阻碍了其实际应用,兼具无机电解质离子电导率高、力学性能好以及有机电解质柔韧性好且不与锂金属反应的复合体系固态电解质已经成为当前研究热点。为了解有机无机复合锂离子电池固态电解质发展态势,本文基于智慧芽Patsnap专利数据库检索结果,总结了全球及中国专利申请数量变化趋势和法律状态,对比了专利主要来源国和主要申请人情况,梳理了技术手段和技术效果之间的关系,重点从有机、无机、添加剂等材料组成,物理共混、三维、多层等复合方式以及特定制备工艺三个维度总结分析了专利技术发展情况。研究发现,我国在有机无机复合锂离子电池固态电解质专利布局方面具有数量优势,但目前申请人较为分散,且技术保护更多限于材料本身,建议加强合作交流,以及对上下游产业的整体技术保护,技术发展方向方面,高无机相用量的三维复合体系具有更佳的综合性能,但从产业化角度,聚合物填充无机颗粒体系可能发展得更快。     

准固态染料敏化太阳电池的制备与性能研究

以AS树脂作为聚合物凝胶电解质基体,乙腈和四氢呋喃作为混合有机溶剂制备准固态染料敏化太阳电池.经过各个组成的优化,聚合物凝胶电解质电导率(30℃)达到5.11mS·cm-1,准固态染料敏化太阳电池的光电转换效率在100mW·cm-2光强下达2.56%.通过在聚合物凝胶电解质中加入氮杂环类添加剂吡啶和1-甲基咪唑,准固态染料敏化太阳电池的光电转换效率在100mW·cm-2光强下分别提高到3.09%和3.00%.     

固态锂硫电池电解质及其界面问题研究进展

固态锂硫(Li-S)电池通过固态电解质代替传统液态电解液体系,有望同时解决液态Li-S电池多硫化物的穿梭效应、锂金属与液态电解液的副反应、安全性能差等关键科学问题,发挥其高稳定性、高能量密度的优势.然而,固态Li-S电池在固态电解质和电极/电解质界面问题上面临着巨大挑战,本文详细介绍了硫化物固态电解质和聚合物基体电解质在Li-S电池中的研究进展,并重点分析了电极/电解质固-固界面接触问题.针对硫化物固态电解质存在的本征缺陷,阐述了改善固态电解质化学及电化学稳定性的方法;针对有机聚合物电解质,总结分析了影响其离子电导率的关键因素及提升方法.在电极/电解质界面问题方面,揭露了影响界面离子传输及界面稳定性的本征特性,并总结了近年来报道的针对正(负)极/电解质界面离子传输低的改进方法.最后指出要有针对性的解决不同种类电解质的本征缺陷,并结合科学模拟深入研究界面传输机制,在实践中对电极/电解质界面结构的合理设计,对固态Li-S电池的实用化具有重要意义.     

聚合物固态电解质设计策略

电解质作为锂离子电池中最为关键的部分之一,决定了锂离子电池的性能。固态电解质相比传统的电解液具有良好的机械强度、优越的安全性等,其中聚合物固态电解质不仅极大降低了锂离子电池的安全隐患,同时表现出优异的机械加工性能,具有良好的弹性和柔韧性,易制备加工成不同的形状。相较于氧化物固态电解质,聚合物固态电解质的柔性使其能很好地贴合电极,阻抗低,合成条件较为简易,对温度、压力等环境要求不苛刻,适宜规模化生产。但聚合物固态电解质的发展应用仍然存在诸多阻碍,在室温下,其离子电导率远远达不到目前对于锂离子电池能量密度的理想需求。既要兼顾聚合物的离子电导率,又要尽可能保留机械强度,是目前需要解决的首要问题。需要搞清楚在分子层面影响聚合物固态电解质离子电导率和高压稳定性的因素,同时探索新型聚合物、共聚物、复合型材料用于其制备中。调节分子间相互作用是一种有前途的提高离子电导率的解决方案。目前相关研究主要集中在开发新型聚合物、开发有效添加剂、针对不同电池系统优化聚合物固态电解质的微观结构三个方面。     

Recent research progress on polymer electrolytes for dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) have attracted large attention due to their easy fabrication, low cost and high conversion efficiency. Electrolytes play an important role in the photovoltaic performance of the DSSCs and many efforts have been contributed to study different kinds of electrolytes with various characteristics such as liquid electrolytes, polymer electrolytes and so on. Because the leakage and the volatilization of liquid electrolytes hinder their practical applications in the DSSCs, polymer electrolytes with high ionic conductivity, excellent thermal stability and long-term stability of the DSSCs based on them are alternatives to liquid electrolytes especially for the quasi-solid-state DSSCs. In this paper, research on solid polymer electrolytes is summarized and the influence of salt concentration on ionic conductivity of solid polymer electrolytes is described and thoroughly explained. On the other hand, the advantages of gel polymer electrolytes (GPEs) are introduced. The factors affecting the ionic conductivity of GPE and the performance of their DSSCs, consisting of the polymer concentration and type, the iodide salts, the solvents and the temperature are discussed. The tendency and the reasons of their influence are expounded in detail. To enhance the properties of GPE, many strategies are taken such as the fabrication of porous structure in the GPE membrane, the incorporation of proton donors, the introduction of inorganic nanoparticles and the addition of pyridine derivatives. Their improving effect and the causes for the enhancement are set forth.     

锂离子电池用（聚）离子液体电解质

锂离子电池已广泛应用于便携式电子设备和电动汽车等领域,然而商用锂离子电池中含有大量易燃的碳酸酯类有机溶剂,容易造成安全隐患。离子液体具有蒸汽压低、化学结构设计多样性、热稳定性及电化学稳定性优异等优点,可以用来代替易燃有机溶剂,在电化学储能领域具有广阔的应用前景。聚离子液体是一类聚合物重复单元上含有阴、阳离子的新型聚合物电解质材料,兼具离子液体和聚合物固态电解质不漏液、易于加工的优势。根据离子液体和聚离子液体化学结构的设计合成及其在锂离子电池中的应用形式,综述了近年来离子液体电解质的研究进展,并提出了离子液体电解质未来的应用挑战和发展方向。     

PVDF基准固态染料敏化太阳电池的研究

以聚偏氟乙烯(PVDF)为凝胶剂,分别将有机溶剂、离子液体电解质固化,并采用这两种体系的电解质分别封装成染料敏化太阳电池,测试了凝胶剂的加入量对太阳电池光电特性的影响,同时利用交流阻抗谱分析了聚合物的加入对抑制暗电流的作用。其中,有机溶剂电解质中PVDF的质量分数分别为5%、20%、25%;离子液体(甲基-丙基咪唑,MPII)电解质中PVDF的质量分数分别为0%、1%、10%。实验中制备的准固态小面积(0.25cm~2)封装电池光电转换效率均高于5.3%,PVDF含量为25%的有机溶剂型准固态电池的效率达到5.92%。此外,实验中还制备了密封的1cm~2的准固态电解质电池,并获得了6.26%的效率,此时对应的J_(SC)=15.4mA/cm~2,V_(OC)=0.672V,FF=60.5%。     

Polymer electrolytes for dye-sensitized solar cells prepared by photopolymerization of PEG-based oligomers

We report on the preparation and characterization of novel polymer electrolyte membranes for quasi-solid dye-sensitized solar cells. New methacrylic–acrylic gel-polymer electrolytes were prepared by photo-polymerization of mono/di-functional monomers. The crosslinked films were self standing, transparent and flexible. They were swelled by an iodine–iodide solution, obtaining a stable gel, where the polymeric network acts as a cage to retain the liquid, preventing its evaporation. Such a system combines the cohesive property of a solid with the high ionic conductivity of a liquid. The evaluation of the structural and physical-chemical characteristics of the polymer, combined with the electrical characterization of the membranes by means of the electrochemical impedance spectroscopy, allowed us to investigate the structure/property relationship of the material. The electric characterizations of the solar harvester based on the gel-polymer electrolyte showed a maximum photovoltaic conversion efficiency of 4.41%. Moreover, a significant improvement in the durability of the device was demonstrated with respect to the liquid electrolyte-based counterpart.     

Recent advances of electrolytes for sodium-ion batteries

作为一种新型的储能电池体系,钠离子电池具有资源丰富、成本低、比容量较高等优点,近年来引起了全世界范围内的广泛关注。电解质是制备高性能,长循环寿命,安全性良好的钠离子电池的关键材料之一。本文简要介绍有机电解质、水系电解质、离子液体电解质、固体聚合物电解质、无机固态复合电解质和凝胶态聚合物电解质等体系在钠离子电池中的研究进展,讨论这些电解质体系的电导率、电化学窗口、热稳定性等特点。目前应用在钠离子电池中较为成熟的是有机电解质,展现了良好的综合性能,但安全性仍有待改善。而安全性能较好的离子液体电解质、固体电解质及凝胶态电解质还有许多基础科学需要探索,并且需要考虑成本、电导率、机械强度等诸多因素。基于上述评述,展望了钠离子电池电解质的未来发展。     

Quasi solid state polymer electrolyte with binary iodide salts for photo-electrochemical solar cells

Quasi-solid-state polymer electrolytes can be used in dye sensitized solar cells (DSSCs) in order to overcome various problems associated with liquid electrolytes. Prior to fabricating commercially viable solar cells, the efficiency of quasi solid state DSSCs needs to be improved. Using electrolytes with a binary iodide mixture is a novel technique used to obtain such efficiency enhancement. In this work we report both conductivity and solar cell performance enhancements due to incorporation of a mixture containing LiI and tetrahexylammonium iodide in a quasi-solid-state electrolyte. The conductivity of the electrolyte increases with added amounts of LiI and thus the highest conductivity, 3.15 × 10⁻³ S cm⁻¹ at 25 °C, is obtained for the electrolyte 100 wt% LiI. The predominantly ionic behavior of the electrolytes was established from dc polarization measurements. The iodide ion conductivity, measured using iodine pellet electrodes decreased somewhat with increasing amount of LiI even though the overall conductivity increased. However, the highest efficiency was obtained for the DSSC containing a polymer electrolyte with Hex₄N⁺I^¯:LiI = 1:2 mass ratio. This cell had the largest short circuit current density of about 13 mA cm⁻² and more than 4% overall energy conversion efficiency. The results thus show that electrolytes with Hex₄N⁺I^¯/LiI mixed iodide system show better DSSC performance than single iodide systems.     

Improved stability quasi-solid-state dye-sensitized solar cell based on polyether framework gel electrolytes

We report three improved stability dye-sensitized TiO₂ photoelectrochemical cells using quasi-solid polymer electrolytes containing poly(propylene oxide) (PPO), poly(ethylene oxide) (PEO) or poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (P₁₂₃). After introducing the polyether into the liquid electrolyte, the parameters of these quasi-solid-state solar cells are 90% comparable to that of the liquid photochemical cells, although the conductivities of these polyether framework gel electrolytes are lower than that of the bulk liquid electrolyte. The different morphologies of dried liquid electrolyte and the polyether gel electrolytes are characterized with an atomic force microscope (AFM) to explain the better stability exhibited by the polyether gel electrolytes.     

Novel thixotropic gel electrolytes based on dicationic bis-imidazolium salts for quasi-solid-state dye-sensitized solar cells

Novel thixotropic gel electrolytes have been successfully prepared by utilizing oligomeric poly(ethylene oxide) (PEO)-based bis-imidazolium diiodide salts and hydrophilic silica nanoparticles for application in quasi-solid-state dye-sensitized solar cells (DSSCs). The thixotropic gel-state of the ionic liquid-based composite electrolytes is confirmed by observing the typical hysteresis loop and temporary hydrogen bonding. On using the PEO-based composite electrolyte, a quasi-solid-state DSSC exhibited highly improved properties such as easy penetration of the electrolyte into the cell without leakage, long-term stability, high open-circuit voltage without the use of 4-tert-butylpyridine, and a high energy-conversion efficiency of 5.25% under AM 1.5 illumination (100 mW cm⁻²).