关键词： Composite solid electrolytes (CSEs)   L1.5Al0.5Ti1.5(PO4)(3) (LATP)   PEO polymer   All-solid-state lithium rechargeable batteries  

摘要： Traditional liquid batteries have been plagued by safety, and highly stable all-solid-state battery is one of the main methods to solve this problem. Solid electrolytes have been accelerating development as a core component of all-solid-state batteries. A composite solid electrolytes (CSEs) composed of an organic polymer and an inorganic solid ceramic has been widely concerned, which can take into consideration the advantages of both and avoid disadvantages. Here, we report CSEs composed of LATP ceramic particles and PEO polymer matrix. The structure, morphology and electrochemical properties of LATP and CSEs are systematically studied. When the LATP complex is 15%, the ion conductivity reaches 1.00 x 10(-4) ***(-1) at 30 degrees C, the lithium ion transference number is 0.37, and the electrochemical window is as high as 5.2 V. The all-solid-state lithium batteries has a reversible capacity of 136.0 mA h g(-1) after 100 cycles, and has excellent rate performance.

关键词： Composite solid polymer electrolyte   High ionic conductivity   In-situ thermal study   Thermal safety   Solid-state lithium battery  

摘要： The low room-temperature ionic conductivity, narrow voltage window, and poor thermal stability of solid polymer electrolyte hinder the application of high energy density, safer solid-state lithium batteries (SLBs). Hence, we developed a novel composite solid polymer electrolyte (CSPE) with high room-temperature ionic conductivity (2.4 x 10(-4) S cm(-1)), wide voltage window (similar to 4.8 V), and excellent thermal stability (similar to 330 degrees C) by combining Li64La3Zr1.4Ta0.6O12 ceramic filler with poly(vinylidene fluoride) (PVDF) polymer and bis(trifluoromethane)sulfonimide lithium (LiTFSI) salt. Free-standing, scalable, and mechanically robust CSPE separately coupled with LiFePO4 and high-voltage LiNi1/3Co1/3Mn1/3O2 cathodes vs lithium anode demonstrated stable cycling. More importantly, we in-situ measured the thermal stable window (177 degrees C) with a small heat release (189 J g(-1)) during the thermal runaway of the entire CSPE coin cell. In contrast, the liquid electrolyte cell delivered a depressing thermal stable window (157 degrees C) and release a significant amount of heat (812 J g(-1)). The superior thermal safety of CSPE cell can be ascribed to the solid-state property and outstanding thermal stability of the CSPE. Most notably, this work not only proposes a promising CSPE but also highlights a reference for in-situ quantitative study on the thermal safety of entire SLBs.

关键词： Upper-Division Undergraduate   Polymer Chemistry   Hands-On Learning/Manipulatives   Interdisciplinary/Multidisciplinary   Materials Science   Electrochemistry   Laboratory Instruction   Electrolytic/Galvanic Cells/Potentials   Solid State Chemistry   Analytical Chemistry  

摘要： All-solid-state polymer electrolytes (SPEs) have been regarded as an advisible alternative for simultaneously overcoming the safety issues and high energy density demands presented in traditional lithium batteries, and they represent the development orientation of energy storage devices. This course describes the preparation of a cross-linked and helical polyurethane modified poly(ethylene oxide) (PEO@HPU) and its utilization as the SPE in lithium batteries, which can be used to teach upper-division undergraduates the principle of energy storage devices and the role of liquid-free electrolytes. Fourier transform infrared (FTIR) and H-1 nuclear magnetic resonance (NMR) spectroscopies are used to determine the structure of the polymers. The ionic conductivity, lithium ion transference number, and electrochemical window of PEO@HPU are measured through an electrochemical workstation. The lithium batteries assembled by students are evaluated via a battery testing system. The modification by the special helical polymer obviously improves the electrochemical and battery performance of the PEO-based SPE. Upon completion of the experiment, students will understand the structure-activity relationship in materials science and propose new suggestions for designing advanced SPEs. This experiment requires well-prepared laboratory chemicals as well as long-term processes, so it is suitable to be considered as a project. Meanwhile, it can be also used for senior projects and interdisciplinary projects between engineering and science.

关键词： 安全性   固态聚合物锂电池   热失控   电池量热仪  

摘要： 锂离子电池安全性至关重要,本次研究利用BTC-130电池量热仪对扣式固态聚合物锂电池、扣式液态锂金属负极电池和18650型锂离子电池进行热失控行为研究。结果表明:18650型锂离子电池热失控起始温度为150℃且热失控放热剧烈,各副反应随热失控同步发生,自放热反应被掩盖无法在温度-时间(T-t)曲线中单独体现。而扣式电池活性物质少、自放热较少,热失控起始温度滞后,温度-时间(T-t)曲线中可以清晰地展现电池升温过程中各个自放热副反应。固态聚合物电池在150℃时无隔膜熔融导致内短路现象,180℃时无碳酸酯溶剂大量气化致电池壳破裂现象,其热失控触发机制是正极材料高温释氧,再与聚合物和熔融锂发生氧化还原反应,聚合物固态电池的安全性优于相应的液态电解质电池。

关键词： Poly(ε-caprolactone)   Polymer membrane   Solid polymer electrolyte   All-solid-state battery   Poly(ether imide)  

摘要： Solid polymer electrolytes composed of poly(ε-caprolactone) (PCL) and lithium bis(trifluoromethane) sulfonylimide (LiTFSI) salt were prepared for investigating their electrochemical properties. The optimized solid polymer electrolyte showed ionic conductivities of 2.5 × 10⁻⁵ and 1.6 × 10⁻⁴ S cm⁻¹ at room temperature and 55 °C, respectively. Dimensional stability was improved by infiltrating PCL-based solid polymer electrolyte into the porous polymer membranes prepared from poly(ether imide) (PEI), polyacrylonitrile (PAN) and non-woven polypropylene (PP) membranes. Due to the highly porous nature and good compatibility of the PEI membrane toward the PCL-based solid polymer electrolyte, a solid-state Li/LiNi_0.6Co_0.2Mn_0.2O₂ cell assembled with a solid polymer electrolyte employing a PEI membrane exhibited the best cycling performance. Based on our results, this highly porous PEI membrane is proposed as a promising supporting membrane for enhancing the mechanical stability of amorphous solid polymer electrolytes for applications in all-solid-state lithium batteries.

关键词： all-solid-state batteries   solid composite polymer electrolytes   ionic conductivity   poly-caprolaclone diol   trimethyl phosphate  

摘要： Solid polymer electrolytes (SPEs) with the advantages of high safety, low volatility, and the ability to suppress Li dendrites are highly desirable to be used in next generation high-safety and high-energy lithium-ion batteries. The exploration of SPEs with superior comprehensive properties has received extensive attention for high-performance all-solid-state batteries (ASSBs). Herein, a sandwich-like nanofibrous membrane-reinforced poly-caprolaclone diol and trimethyl phosphate (TMP) composite polymer electrolyte (CPE) has been designed by a facile "solvent-free" solution-casting method. Specifically, the flame-retardant TMP is employed as a plasticizer, which can improve the ionic conductivity effectively. The as-prepared solid electrolyte exhibits superior comprehensive performance in terms of high ionic conductivity, wide electrochemical window, good compatibility with lithium metal, and superior thermal stability. Furthermore, the assembled Li//LiFePO4 ASSBs with this solid CPE show outstanding cycling stability and high average discharge capacity at room temperature (30 degrees C). Undoubtedly, our study provides a new facile method and a qualified solid electrolyte material for next generation high-performance ASSBs.

关键词： Lithium thin film batteries   Flexible batteries   Excimer laser annealing   Microbatteries   LiNi0.5Mn1.5O4  

摘要： Recently, all-solid-state lithium batteries have attracted great attention due to their safe operation without risk of explosion under high operating voltage. However, integrating all solid layers on flexible polymer substrate has been hampered by conflicts between the high crystallization temperature and the endurable temperature of the polymer substrate. In this work, we present a simple fabrication method for all-solid-state flexible lithium batteries that are directly integrated on a polymer substrate. Using excimer laser annealing technique, we are able to selectively crystalize the amorphous cathode layer grown on top of the polymer platform without any damage to the substrate. Our flexible battery is bendable up to a curvature radius of 9 mm without mechanical breakdown, and has an initial capacity of 20 mu A h mu m(-1) cm(-2) at a 0.2 C-rate. Our approach using laser annealing provides new opportunities for integrating all-solid-state lithium thin film batteries on a broader range of platforms.

关键词： 全固态聚合物电解质   离子电导率   聚合物锂电池  

摘要： 随着储能电源和电子产品以及电动汽车的迅速发展,开发高能量密度的锂离子电池已经成为现阶段研究的重点方向之一。目前,较广泛使用的液态锂离子电池,由于容易发生有机液态电解质的泄漏、燃烧、爆炸和短路等问题,存在非常大的安全隐患。因此,迫切需要开发能量密度更高,安全性更加好的锂离子电池。与现有的有机液态电解质相比,全固态聚合物电解质(All-solid-state polymer electrolyte,ASPE)具有理论比容量更高、结构可设计性强、易于大规模生产制造、排除了泄漏液体等体系安全性能好的优点,是一类具有广泛应用前景的电解质。ASPEs在锂离子电池中起到了主导作用,研究者们对其进行了大量的科研工作。本文结合并比较了典型的ASPEs(聚醚、聚酯、聚氨酯、聚硅氧烷)的最新科研进展以及本课题组的工作,回顾了这几种固态聚合物的发展,对高性能锂电池全固态电解质的制备设计、新型锂电池、界面调控和制备工艺成型等方面作了阐述,并对其未来的研究做出展望。

关键词： Solid state battery   Polymer electrolyte   Nickel phosphate   High ionic conductivity   Interface stability  

摘要： Solid-state electrolytes with high ionic conductivity, large electrochemical window, and excellent stability with lithium electrode are needed for high-energy solid-state lithium batteries. In this work, a novel polyethylene oxide (PEO)-Lithium bis(trifluoromethylsulphonyl)imide (LiTFSI)-nanocomposite-based polymer electrolyte was prepared by using nickel phosphate (VSB-5) nanorods as the filler. The ionic conductivity of the obtained PEO-LiTFSI-3%VSB-5 solid polymer electrolyte was found to be as high as 4.83 x 10(-5) ***(-1) at 30 degrees C and electrochemically stable up to about 4.13 V versus Li/Li*. The enhanced ionic conductivity was attributed to the reduced crystallinity of the PEO and the interaction between VSB and 5 and PEO-LiTFSI. In addition, the solid polymer electrolyte exhibited improved compatibility to the lithium metal anode with excellent suppression of lithium dendrites. The assembled LiFePO4/Li battery with the PEO-LiTFSI-3%VSB-5 solid polymer electrolyte showed better rate performance and higher cyclic stability than the PEO-LiTFSI electrolyte. It is demonstrated that this new solid polymer hybrid should be a promising electrolyte applied in solid state batteries with lithium metal electrode. (C) 2020 Elsevier Inc. All rights reserved.

关键词： solid-state electrolytes   Li-based batteries   fireproof   polymer-polymer composite   lightweight  

摘要： Safety issues in lithium-ion batteries have raised serious concerns due to their ubiquitous utilization and close contact with the human body. Replacing flammable liquid electrolytes, solid-state electrolytes (SSEs) is thought to address this issue as well as provide nmatched energy densities in Li-based batteries. However, among the most intensively studied SSEs, polymeric solid electrolyte and polymer/ceramic composites are usually flammable, leaving the safety issue unattended. Here, we report the first design of a fireproof, ultralight-weight polymer-polymer SSE. The SSE is composed of a porous mechanic enforcer (polyimide, PI), a fire-retardant additive (decabromodiphenyl ethane, DBDPE), and a ionic conductive polymer electrolyte (poly(ethylene oxide)/lithium bis-(trifluoromethanesulfonyl)imide). The whole SSE is made from organic materials, with a thin, tunable thickness (10-25 mu m), which endorse the energy density comparable to conventional separator/liquid electrolytes. The PI/DBDPE film is thermally stable, nonflammable, and mechanically strong, preventing Li-Li symmetrical cells from short-circuiting after more than 300 h of cycling. LiFePO4/Li half cells with our SSE show a high rate performance (131 mAh g(-1) at 1 C) as well as cycling performance (300 cycles at C/2 rate) at 60 degrees C. Most intriguingly, pouch cells made with our polymer-polymer SSE still functioned well even under flame abuse tests.