聚合物复合电解质的界面结构与控制

本文主要讨论了聚合固体电解质与聚合物,增塑剂和无机物等复合形成的多相聚合物复合电解质中,界面结构对离子电导率和机械性能的影响,指出选择适当的改性剂及复合方法,控制界面的结构和形态,形成尽可能多的高导电的界面,是获得电导率高和机械性能良好的聚合物固体电解质的有效途径。     

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。     

PEO类聚合物基体的改性及其高性能电解质材料研究的新进展

聚氧化乙烯(PEO)是聚合物电解质传统的基体材料,它最大的优势在于在不添加任何增塑剂的情况下,可以与锂盐形成稳定的络合物,但PEO易于结晶,使离子电导率降低。研究表明:采用共混、接枝、共聚、交联以及与无机物复合等方法对PEO进行改性,可以进一步提高此类聚合物电解质的性能。重点对PEO类聚合物基体的改性及其高性能固体聚合物电解质材料研究的新进展进行介绍,并对其研究前景做了展望。     

石墨烯基聚合物复合电解质的设计、性能及其应用研究进展

固态电化学器件具有柔性好、安全性能高及能量密度高等优点,属于极有前景的新一代化学能源器件。固态电解质是实现电化学器件固态化的关键,其中石墨烯基聚合物复合电解质由传统聚合物电解质发展而来,是一类含有石墨烯纳米填料和聚合物基体的新型固态电解质,具有较高的离子电导率、良好的加工性能及优异的界面特性,现已成为固态电化学器件研发中备受关注的电解质材料。本文着重讨论了近年来石墨烯基聚合物复合电解质的结构设计、性能机制及在各种电化学储能器件中应用的研究进展。      

复合型聚醚聚氨酯固体电解质的制备及交流阻抗分析

合成了1种线性聚醚聚氨酯,并以此聚合物为基体加入O/Li=16(摩尔比)的锂盐,分别掺入纳米SiO2、纳米TiO2制备了两类复合聚合物固体电解质(CSPE).在室温下,纳米SiO2复合型聚合物固体电解质的电导率最大,达到6.40×10-6S/cm.通过红外光谱、热分析及交流阻抗等手段研究了电解质本体,以及掺入无机氧化物粒子之后其质量分数与离子电导率之间的关系.结果表明,纳米SiO2质量分数达到15%,纳米TiO2质量分数达到25%时,离子电导率最大.在室温下,加入纳米SiO2比加入纳米TiO2的离子电导率要高;但随着温度的升高,这种差距越来越小.     

凝胶聚合物电解质用于锂离子电池的研究进展

电解质在电化学储能中起着至关重要的作用。在锂离子电池(LIB)中,液体电解质(LE)在几十年的发展中表现出了优异的性能,如高的离子电导率(10^-3S/cm)和与电极良好的接触。然而,LE中的安全问题以及由枝晶生长引起的性能退化严重阻碍了LIB的实际应用。因此,聚合物电解质(PE)有望取代LE。固体聚合物电解质(SPE)虽然有很好的安全性和机械性能,但其受温度限制,离子电导率较低,且与电极接触较差,电池循环性较差。凝胶聚合物电解质(GPE)结合两者的优点,被认为是现有有机液体电解质的有效替代品,它可以用来制造更安全的锂电池。对现有聚合物基体的交联、共聚和混合改性——能够提高电解质的电化学性能的方法进行了综述。同时也对GPE在LIB中的最新研究进展进行了综述,并介绍了新型生物基凝胶电解质基体。最后,展望了制造性能优异的基于GPEs的LIB电池面临的挑战和发展方向。     

新型全固态复合聚合物电解质的制备与应用

高分子聚合物与碱金属盐的络合物具有离子导电性,是电化学材料领域在过去25年里的重要发现之一,它的发现揭开了人们研究固体电解质的序幕。高分子全固态复合电解质由于具有良好的离子传输能力、成膜性能和力学性能,已成为电致变色器件等电化学装置中的重要组成部分。总结了聚合物电解质的种类,电导率的影响因素与表征方法,分析了全固态聚合物电解质材料的制备工艺与应用。新型复合聚合物电解质材料具有很好的市场前景和十分明显的社会经济效益,对此课题的进一步深入研究和技术上的突破有可能导致新能源材料领域,尤其是电池材料领域的一场新的技术革命。     

纳米SiO2/LiClO4/PVDF-HFP复合凝胶聚合物电解质的制备及其电化学性能

为了解决液态电解质锂离子电池存在的安全性问题,以偏氟乙烯和六氟丙烯的共聚物(PVDF-HFP)为基体,通过加入高氯酸锂(LiC1O4)、增塑剂(碳酸丙烯酯和碳酸二甲酯)、纳米二氧化硅等,制备出了具有高电导率的复合凝胶聚合物电解质.用X射线衍射仪测试聚合物电解质的结构,用交流阻抗法测定其电导率,用线性伏安扫描法研究了该聚合物电解质体系的电化学稳定性,并以其为电解质制备成锂离子电池进行充放电测试.结果表明,在20℃时复合凝胶聚合物电解质的电导率最高可达7.56×10-3S/cm,该电解质在4.6 V以下电化学窗口稳定,以其为电解质的锂离子电池具有良好的电化学性能,说明纳米SiO2/LiC1O4/PVDF-HFP复合凝胶聚合物电解质能满足锂离子电池的应用.     

纳米 SiO 2/ LiClO 4/ PVDF2 HFP复合凝胶聚合物电解质的制备及其电化学性能

为了解决液态电解质锂离子电池存在的安全性问题 , 以偏氟乙烯和六氟丙烯的共聚物( PVDF2 HFP)为基体 , 通过加入高氯酸锂(LiClO 4) 、 增塑剂(碳酸丙烯酯和碳酸二甲酯) 、 纳米二氧化硅等 , 制备出了具有高电导率的复合凝胶聚合物电解质。用 X射线衍射仪测试聚合物电解质的结构 , 用交流阻抗法测定其电导率 , 用线性伏安扫描法研究了该聚合物电解质体系的电化学稳定性 , 并以其为电解质制备成锂离子电池进行充放电测试。结果- 3表明 , 在 20℃ 时复合凝胶聚合物电解质的电导率最高可达 7. 56×10 S/ cm , 该电解质在 41 6 V 以下电化学窗口稳定 , 以其为电解质的锂离子电池具有良好的电化学性能 , 说明纳米 SiO 2/ LiClO 4/ PVDF2 HFP复合凝胶聚合物电解质能满足锂离子电池的应用。     

固态电解质中的聚合物复合体系研究进展

固态聚合物电解质因其质量轻、柔性好,且与电极材料接触良好、界面阻抗小,成为开发新一代高能量密度、高安全性乃至高柔韧性电化学器件的潜在材料,近年来获得了广泛关注。但因其离子电导率低、力学性能差等缺陷也成为限制其进一步商业化的关键问题。通过交联、共混、共聚等手段组成聚合物的复合体系有可能很好地解决这些问题,因此本文首先对聚合物中的离子导电机理进行了简要介绍,旨在从原理的角度阐释上述问题的解决策略;随后综述了近年来多种聚合物基复合电解质在电化学器件中的应用以及改性策略。最后对复合固态聚合物电解质目前面临的基础研究和实际应用问题进行了讨论,给出了解决这些问题的建议,以期为新型聚合物复合固态电解质的设计与制备提供新思路。     

超级电容器电解质研究进展

电解质作为超级电容器的重要组成部分,对器件性能起着关键性作用。本文对近些年来超级电容器各种电解质,包括水系、有机液体、离子液体、固态/准固态聚合物电解质和氧化还原体系电解质的特点和最新研究成果进行了描述;重点介绍了固态/准固态聚合物电解质的分类及其性能研究概况。提出了发展电位窗口宽、离子电导率高、电化学性能稳定的离子液体和机械强度等综合性能优良的凝胶聚合物电解质是将来超级电容器电解质发展领域的趋势,最后对超级电容器电解质的发展前景进行了展望。     

锂离子电池电解质的最新研究进展

综述了近几年来电解质（即液态电解质和固态电解质）的研究进展，主要是介绍如何提高液态电解质的性能和固态电解质的性能。对液态电解质主要是电化学稳定性的提高，而对固态电解质则包括对离子电导率、电化学稳定、机械性能等的提高。虽然在锂离子电池中，对电池性能起决定作用的是电极材料，但只有对正、负极匹配合适的和性能好的电解质才能达到对锂离子电池性能的优化和提高。因而电解质性能的好坏对锂离子电池的性能有重要的影响。     

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.     

P(MMA-VAc-LiAA)聚合物电解质的制备及表征

以甲基丙烯酸甲酯(MMA)、醋酸乙烯酯(VAc)和丙烯酸锂(LiAA)为单体,采用种子乳液聚合法制备了(P(MMA-VAc-LiAA)三元共聚物.利用红外光谱(FTIR),核磁共振(~1HNMR),差示扫描量热(DSC) /热重分析(TG),X射线衍射(XRD),扫描电镜(SEM)等方法对聚合物的结构进行了表征.将P(MMA-VAc-LiAA)与LiClO_4共混,采用流延法制备了聚合物电解质膜,用交流阻抗方法测试了电解质膜的电导率,结果表明,该聚合物电解质室温离子电导率可以达到10~(-3)S/cm.而且离子电导率随着温度的升高而迅速增加,电导率-温度曲线符合Arrhenius方程.机械性能测试结果表明,在P(MMA-VAc)的基础上,引入第三单体LiAA可以改善膜的收缩性与力学性能.     

Thiol-Branched Solid Polymer Electrolyte Featuring High Strength,Toughness, and Lithium Ionic Conductivity for Lithium-Metal Batteries

Lithium-metal batteries (LMBs) with high energy densities are highly desirable for energy storage, but generally suffer from dendrite growth and side reactions in liquid electrolytes; thus the need for solid electrolytes with high mechanical strength, ionic conductivity, and compatible interface arises. Herein, a thiol-branched solid polymer electrolyte (SPE) is introduced featuring high Li⁺ conductivity (2.26 × 10⁻⁴ S cm⁻¹ at room temperature) and good mechanical strength (9.4 MPa)/toughness (≈500%), thus unblocking the tradeoff between ionic conductivity and mechanical robustness in polymer electrolytes. The SPE (denoted as M-S-PEGDA) is fabricated by covalently cross-linking metal–organic frameworks (MOFs), tetrakis (3-mercaptopropionic acid) pentaerythritol (PETMP), and poly(ethylene glycol) diacrylate (PEGDA) via multiple C S C bonds. The SPE also exhibits a high electrochemical window (>5.4 V), low interfacial impedance (<550 Ω), and impressive Li⁺ transference number (t_Li+ = 0.44). As a result, Li||Li symmetrical cells with the thiol-branched SPE displayed a high stability in a >1300 h cycling test. Moreover, a Li|M-S-PEGDA|LiFePO₄ full cell demonstrates discharge capacity of 143.7 mAh g⁻¹ and maintains 85.6% after 500 cycles at 0.5 C, displaying one of the most outstanding performances for SPEs to date.     

Advanced Composite Solid Electrolytes for Lithium Batteries: Filler Dimensional Design and Ion Path Optimization

Composite solid electrolytes are considered to be the crucial components of all-solid-state lithium batteries, which are viewed as the next-generation energy storage devices for high energy density and long working life. Numerous studies have shown that fillers in composite solid electrolytes can effectively improve the ion-transport behavior, the essence of which lies in the optimization of the ion-transport path in the electrolyte. The performance is closely related to the structure of the fillers and the interaction between fillers and other electrolyte components including polymer matrices and lithium salts. In this review, the dimensional design of fillers in advanced composite solid electrolytes involving 0D–2D nanofillers, and 3D continuous frameworks are focused on. The ion-transport mechanism and the interaction between fillers and other electrolyte components are highlighted. In addition, sandwich-structured composite solid electrolytes with fillers are also discussed. Strategies for the design of composite solid electrolytes with high room temperature ionic conductivity are summarized, aiming to assist target-oriented research for high-performance composite solid electrolytes.     

聚硅氧烷对水性聚氨酯聚合物电解质结构形态及电化学性能的影响

将PDMS引入到WPU中,合成了PEO-PDMS混合软段WPU嵌段共聚物,通过改变PDMS的含量得到一系列固态聚合物电解质膜。测试结果表明,PDMS的加入会对聚合物电解质材料的力学性能、微观形态、电化学性能产生显著影响。PDMS的加入可有效地提高聚合物电解质的室温电导率及电化学稳定性,30℃时样品C17-10电导率为1.05×10-4S/cm,其电化学稳定窗口达到5.5V。     

Aliphatic Polycarbonate‐Based Solid‐State Polymer Electrolytes for Advanced Lithium Batteries: Advances and Perspective

Conventional liquid electrolytes based lithium‐ion batteries (LIBs) might suffer from serious safety hazards. Solid‐state polymer electrolytes (SPEs) are very promising candidate with high security for advanced LIBs. However, the quintessential frailties of pristine polyethylene oxide/lithium salts SPEs are poor ionic conductivity (≈10⁻⁸ S cm⁻¹) at 25 °C and narrow electrochemical window (<4 V). Many innovative researches are carried out to enhance their lithium‐ion conductivity (10⁻⁴ S cm⁻¹ at 25 °C), which is still far from meeting the needs of high‐performance power LIBs at ambient temperature. Therefore, it is a pressing urgency of exploring novel polymer host materials for advanced SPEs aimed to develop high‐performance solid lithium batteries. Aliphatic polycarbonate, an emerging and promising solid polymer electrolyte, has attracted much attention of academia and industry. The amorphous structure, flexible chain segments, and high dielectric constant endow this class of polymer electrolyte excellent comprehensive performance especially in ionic conductivity, electrochemical stability, and thermally dimensional stability. To date, many types of aliphatic polycarbonate solid polymer electrolyte are discovered. Herein, the latest developments on aliphatic polycarbonate SPEs for solid‐state lithium batteries are summarized. Finally, main challenges and perspective of aliphatic polycarbonate solid polymer electrolytes are illustrated at the end of this review.     

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.