Poly(VBMIMPF_6)/BMIMPF_6离子凝胶的制备与性能

以1-乙烯基-3-丁基咪唑六氟磷酸盐(VBMIMPF6)为单体,1-丁基-3-甲基咪唑六氟磷酸盐(BMIMPF6)为溶剂和电解质,并以聚乙二醇二丙烯酸酯(PEGDA)为交联剂,采用原位紫外交联的方法制备出了一种新型聚离子液体基离子凝胶电解质。通过扫描电子显微镜、流变性能、力学拉伸和电化学交流阻抗等手段,考察了离子凝胶电解质的微观结构、流变性能、力学性能和电学性能。流变性能测试结果表明,离子凝胶具有很高的储能模量(10~4~10~5 Pa),且温度200℃内储能模量基本保持不变。拉伸性能测试结果表明,体系具有很强的力学性能且拉伸强度达到10~5 Pa数量级。电学性能测试结果表明室温下离子凝胶具有很高的电导率(10~(-4)~10~(-3)S/cm),且电导率随BMIMPF6含量的增加而增大。     

Cross-Link-Dependent Ionogel-Based Triboelectric Nanogenerators with Slippery and Antireflective Properties

Given the ability to convert various ambient unused mechanical energies into useful electricity, triboelectric nanogenerators (TENGs) are gaining interest since their inception. Recently, ionogel-based TENGs (I-TENGs) have attracted increasing attention because of their excellent thermal stability and adjustable ionic conductivity. However, previous studies on ionogels mainly pursued the device performance or applications under harsh conditions, whereas few have investigated the structure–property relationships of components to performance. The results indicate that the ionogel formulation—composed of a crosslinking monomer with an ionic liquid—affects the conductivity of the ionogel by modulating the cross-link density. In addition, the ratio of cross-linker to ionic liquid is important to ensure the formation of efficient charge channels, yet increasing ionic liquid content delivers diminishing returns. The ionogels are then used in I-TENGs to harvest water droplet energy and the performance is correlated to the ionogels structure–property relationships. Improvement of the energy harvesting is further explored by the introduction of surface polymer brushes on I-TENGs via a facile and universal method, which enhances droplet sliding by means of ideal surface contact angle hysteresis and improves its anti-reflective properties by employing the I-TENG as a surface covering for solar cells.     

Sulfide‐Based Solid‐State Electrolytes: Synthesis,Stability, and Potential for All‐Solid‐State Batteries

Due to their high ionic conductivity and adeciduate mechanical features for lamination, sulfide composites have received increasing attention as solid electrolyte in all‐solid‐state batteries. Their smaller electronegativity and binding energy to Li ions and bigger atomic radius provide high ionic conductivity and make them attractive for practical applications. In recent years, noticeable efforts have been made to develop high‐performance sulfide solid‐state electrolytes. However, sulfide solid‐state electrolytes still face numerous challenges including: 1) the need for a higher stability voltage window, 2) a better electrode–electrolyte interface and air stability, and 3) a cost‐effective approach for large‐scale manufacturing. Herein, a comprehensive update on the properties (structural and chemical), synthesis of sulfide solid‐state electrolytes, and the development of sulfide‐based all‐solid‐state batteries is provided, including electrochemical and chemical stability, interface stabilization, and their applications in high performance and safe energy storage.     

Overcoming the Interfacial Limitations Imposed by the Solid–Solid Interface in Solid‐State Batteries Using Ionic Liquid‐Based Interlayers

Li‐garnets are promising inorganic ceramic solid electrolytes for lithium metal batteries, showing good electrochemical stability with Li anode. However, their brittle and stiff nature restricts their intimate contact with both the electrodes, hence presenting high interfacial resistance to the ionic mobility. To address this issue, a strategy employing ionic liquid electrolyte (ILE) thin interlayers at the electrodes/electrolyte interfaces is adopted, which helps overcome the barrier for ion transport. The chemically stable ILE improves the electrodes‐solid electrolyte contact, significantly reducing the interfacial resistance at both the positive and negative electrodes interfaces. This results in the more homogeneous deposition of metallic lithium at the negative electrode, suppressing the dendrite growth across the solid electrolyte even at high current densities of 0.3 mA cm^?2. Further, the improved interface Li/electrolyte interface results in decreasing the overpotential of symmetric Li/Li cells from 1.35 to 0.35 V. The ILE modified Li/LLZO/LFP cells stacked either in monopolar or bipolar configurations show excellent electrochemical performance. In particular, the bipolar cell operates at a high voltage (≈8 V) and delivers specific capacity as high as 145 mAh g^?1 with a coulombic efficiency greater than 99%.     

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。     

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.     

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.     

固态电池中的正极/电解质界面性质研究进展EI北大核心CSCD

锂离子电池是便携式电子产品、电动汽车和智能电网的理想电源。目前使用有机液体电解质的锂离子电池仍然存在安全问题和寿命不足的问题,而使用不燃的固态电解质的固态电池有望解决这些问题。从原理上讲,不燃的固体电解质可以从根本上防止电池的燃烧和爆炸,并且只允许锂离子在固体电解质中传输,可以减少副反应的发生。近年来,随着几种高离子电导率的固态电解质的出现,锂离子在固态电解质中的传输不再是瓶颈。然而,固态电池中各种固态成分具有不同的化学/物理/力学性能,因此在固态电池中存在多种类型的界面,包括松散的物理接触、晶界、化学和电化学反应界面等,这些都可能增加界面离子传输阻力。而正极材料与电解质之间的界面反应尤其复杂,深入理解这些复杂的正极侧界面及其反应特点是实现实用高比能固态电池的必要条件。因此,本文主要回顾了近年来在探索和理解正极/电解质界面上的工作,总结了固态电池中典型的正极侧界面类型及其各自独特的反应特征。     

Preparation of High‐Performance Ionogels with Excellent Transparency,Good Mechanical Strength,and High Conductivity

Ionogels offer great potential for diverse electric applications. However, it remains challenging to fabricate high‐performance ionogels with both good mechanical strength and high conductivity. Here, a new kind of transparent ionogel with both good mechanical strength and high conductivity is designed via locking a kind of free ionic liquid (IL), i.e., 1‐ethyl‐3‐methylimidazolium dicyanamide ([EMIm][DCA]), into charged poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid) (PAMPS)‐based double networks. On the one hand, the charged PAMPS double network provides good mechanical strength and excellent recovery property. On the other hand, the free [EMIm][DCA] locked in the charged double network through electrostatic interaction offers ionic conductivity as high as ≈1.7–2.4 S m^?1 at 25 °C. It is demonstrated that the designed ionogel can be successfully used for a flexible skin sensor even under harsh conditions. Considering the rationally designed chemical structures of ILs and the diversity of charged polymer networks, it is envisioned that this strategy can be extended to a broad range of polymer systems. Moreover, functional components such as conducting polymers, 0D nanoparticles, 1D nanowires, and 2D nanosheets can be introduced into the polymer systems to fabricate diverse novel ionogels with unique functions. It is believed that this design principle will provide a new opportunity to construct next‐generation multifunctional ionogels.     

“Salting out” in Hofmeister Effect Enhancing Mechanical and Electrochemical Performance of Amide-based Hydrogel Electrolytes for Flexible Zinc-Ion Battery

With the development of flexible and wearable electronic devices, it is a new challenge for polymer hydrogel electrolytes to combine high mechanical flexibility and electrochemical performance into one membrane. In general, the high content of water in hydrogel electrolyte membranes always leads to poor mechanical strength, and limits their applications in flexible energy storage devices. In this work, based on the “salting out” phenomenon in Hofmeister effect, a kind of gelatin-based hydrogel electrolyte membrane is fabricated with high mechanical strength and ionic conductivity by soaking pre-gelated gelatin hydrogel in 2 m ZnSO₄ aqueous. Among various gelatin-based electrolyte membranes, the gelatin-ZnSO₄ electrolyte membrane delivers the “salting out” property of Hofmeister effect, which improves both the mechanical strength and electrochemical performance of gelatin-based electrolyte membranes. The breaking strength reaches 1.5 MPa. When applied to supercapacitors and zinc-ion batteries, it can sustain over 7500 and 9300 cycles for repeated charging and discharging processes. This study provides a very simple and universal method to prepare polymer hydrogel electrolytes with high strength, toughness, and stability, and its applications in flexible energy storage devices provide a new idea for the construction of secure and stable flexible and wearable electronic devices.     

Graphene‐Analogues Boron Nitride Nanosheets Confining Ionic Liquids: A High‐Performance Quasi‐Liquid Solid Electrolyte

Solid electrolytes are one of the most promising electrolyte systems for safe lithium batteries, but the low ionic conductivity of these electrolytes seriously hinders the development of efficient lithium batteries. Here, a novel class of graphene‐analogues boron nitride (g‐BN) nanosheets confining an ultrahigh concentration of ionic liquids (ILs) in an interlayer and out‐of‐layer chamber to give rise to a quasi‐liquid solid electrolyte (QLSE) is reported. The electron‐insulated g‐BN nanosheet host with a large specific surface area can confine ILs as much as 10 times of the host's weight to afford high ionic conductivity (3.85 × 10^?3 S cm^?1 at 25 °C, even 2.32 × 10^?4 S cm^?1 at ?20 °C), which is close to that of the corresponding bulk IL electrolytes. The high ionic conductivity of QLSE is attributed to the enormous absorption for ILs and the confining effect of g‐BN to form the ordered lithium ion transport channels in an interlayer and out‐of‐layer of g‐BN. Furthermore, the electrolyte displays outstanding electrochemical properties and battery performance. In principle, this work enables a wider tunability, further opening up a new field for the fabrication of the next‐generation QLSE based on layered nanomaterials in energy conversion devices.     

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。     

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。     

A lithium superionic conductor

Batteries are a key technology in modern society. They are used to power electric and hybrid electric vehicles and to store wind and solar energy in smart grids. Electrochemical devices with high energy and power densities can currently be powered only by batteries with organic liquid electrolytes. However, such batteries require relatively stringent safety precautions, making large-scale systems very complicated and expensive. The application of solid electrolytes is currently limited because they attain practically useful conductivities (10(-2) S cm(-1)) only at 50-80 °C, which is one order of magnitude lower than those of organic liquid electrolytes. Here, we report a lithium superionic conductor, Li(10)GeP(2)S(12) that has a new three-dimensional framework structure. It exhibits an extremely high lithium ionic conductivity of 12 mS cm(-1) at room temperature. This represents the highest conductivity achieved in a solid electrolyte, exceeding even those of liquid organic electrolytes. This new solid-state battery electrolyte has many advantages in terms of device fabrication (facile shaping, patterning and integration), stability (non-volatile), safety (non-explosive) and excellent electrochemical properties (high conductivity and wide potential window).     

Lithium-Ion Battery Separators for Ionic-Liquid Electrolytes: A Review

Ionic liquids (ILs) are widely studied as a safer alternative electrolyte for lithium-ion batteries. The properties of IL electrolytes compared to conventional electrolytes make them more thermally stable, but they also have poor wetting with commercial separators. In a lithium-ion battery, the electrolyte should completely wet out the separator and electrodes to reduce the cell internal resistance. Investigations of cell materials with IL electrolytes have shown that the wetting issues in IL–electrolyte cells are most likely due to poor separator compatibility, not electrode compatibility. A compatible separator must be developed before IL electrolytes can be used in commercial lithium-ion batteries. Herein, separators for IL electrolytes, including commercial and novel separators, are reviewed. Separators with different processing methods, polymers, additives, and different IL electrolytes are considered. Collated, the separator studies show a strong correlation between ionic conductivity and membrane porosity, even more than the electrolyte type. The challenge of a suitable separator for IL electrolytes is not solved yet. Herein, it is revealed that a separator for IL electrolytes will most likely require a combination of high thermal and mechanical stability polymer, ceramic additives, and an optimized manufacturing process.     

Exploiting High-Voltage Stability of Dual-Ion Aqueous Electrolyte Reinforced by Incorporation of Fiberglass into Zwitterionic Hydrogel Electrolyte

Rechargeable zinc aqueous batteries are key alternatives for replacing toxic, flammable, and expensive lithium-ion batteries in grid energy storage systems. However, these systems possess critical weaknesses, including the short electrochemical stability window of water and intrinsic fast zinc dendrite growth. Hydrogel electrolytes provide a possible solution, especially cross-linked zwitterionic polymers that possess strong water retention ability and high ionic conductivity. Herein, an in situ prepared fiberglass-incorporated dual-ion zwitterionic hydrogel electrolyte with an ionic conductivity of 24.32 mS cm⁻¹, electrochemical stability window up to 2.56 V, and high thermal stability is presented. By incorporating this hydrogel electrolyte of zinc and lithium triflate salts, a zinc//LiMn_0.6Fe_0.4PO₄ pouch cell delivers a reversible capacity of 130 mAh g⁻¹ in the range of 1.0–2.2 V at 0.1C, and the test at 2C provides an initial capacity of 82.4 mAh g⁻¹ with 71.8% capacity retention after 1000 cycles with a coulombic efficiency of 97%. Additionally, the pouch cell is fire resistant and remains safe after cutting and piercing.     

固态锂电池用MOF/聚氧化乙烯复合聚合物电解质

固态聚合物电解质具有柔韧性好和易于加工的优势, 可制备各种形状的固态锂电池, 杜绝漏液问题。但固态聚合物电解质存在离子电导率低以及对锂金属负极不稳定等问题。本研究以纳米金属-有机框架材料UiO-66为聚合物电解质的填料, 用于改善电解质的性能。UiO-66与聚氧化乙烯(poly(ethylene oxide), PEO)链上醚基的氧原子的配位作用以及与锂盐中阴离子的相互作用, 可显著提高聚合物电解质的离子电导率(25 ℃, 3.0×10 ^-5S/cm; 60 ℃, 5.8×10 ^-4 S/cm), 并将锂离子迁移数提高至0.36, 电化学窗口拓宽至4.9 V。此外, 制备的PEO基固态电解质对金属锂具有良好的稳定性, 对称电池在60 ℃、0.15 mA·cm ^-2电流密度下可稳定循环1000 h, 锂电池的电化学性能得到显著改善。     

Performance enhancement induced by electrospinning of polymer electrolytes based on poly(methyl methacrylate-co-2-acrylamido-2-methylpropanesulfonic acid lithium)

A series of novel fibrous polymer electrolytes with high ionic conductivity based on electrospun poly(methyl methacrylate-co-2-acrylamido-2-methylpropanesulfonic acid lithium) (P(MMA-co-AMPSLi)) membranes were prepared and characterized. P(MMA-co-AMPSLi) was synthesized by free radical copolymerization of MMA and AMPS, followed by ion exchange of the H⁺ with Li⁺. The fibrous polymer electrolytes were fabricated by immersing the electrospun P(MMA-co-AMPSLi) membranes into the liquid electrolyte. Fourier transform infrared spectroscopy and ¹H-nuclear magnetic resonance were used to characterize the structure of the copolymers. Thermogravimetric analysis was applied to investigate the thermal properties of the copolymers. Scanning electromicroscope was employed to observe the morphology of electrospun membranes before and after soaking the liquid electrolyte. AC impedance and linear sweep voltammetry were adopted to measure the electrochemical properties of the fibrous polymer electrolytes. The incorporation of the AMPSLi units effectively improved the electrospinnability of the copolymer, increased the dielectric constants of the electrospun membranes, and enhanced the dimensional stability by maintaining the pore structures even after the membranes absorbing large amounts of liquid electrolytes. As a result, the ionic conductivity of the polymer electrolytes increased with the increase in the molar ratio of AMPSLi units, and the highest ion conductivity was up to 4.12 × 10⁻³ S cm⁻¹ at room temperature. Meanwhile, the polymer electrolytes studied in this work exhibited a sufficient electrochemical stability (up to 5.0 V) that allows the safe operation in lithium-ion batteries.     

功能化离子液体在锂二次离子电池中的应用

离子液体由于具有热稳定性好、电导率高、质材料在不同电池体系中的应用成为当前研究的热点。面的阐述,并对其应用前景进行了展望。电化学窗口宽、不挥发、不燃烧等特点,其作为新一代功能化电解本文对功能化的离子液体在电池体系中的最新研究进展作了较为全