锂离子电池高压电解液应用及电化学性能分析

在锂离子电池中电解液是传递锂离子的载体,正是通过电解液实现电池正极、负极及隔膜的连接,由此可见,电解液的品质会直接影响锂离子电池的性能。传统水系电解液的理论分解电压仅1.23V,所以铅酸蓄电池主要应用水系电解液其最高电压仅为2V,而锂离子电池工作电压至少在3~4V,因此研究锂离子电池高压电解液的应用及电化学性能具有重要意义。以磷酸铁锂离子电池(LiFePO_4)使用草酸二氟硼酸锂(LiBC_2O_4F_2)基电解液为例,分析LiBC_2O_4F_2的电化学性能。     

硅烷添加剂在锂离子电池电解液中的应用

硅烷添加剂因具有高热稳定性、低可燃性、无毒性、高电导率和高分解电压等优点,近年来成为了锂离子电池电解液新型添加剂的研究热点。本文重点介绍了在硅烷电解液添加剂中Si—O结构、Si—N结构所发挥的作用以及机理,最后对硅烷添加剂的进一步研究趋势和应用前景进行了展望。     

气相色谱法在锂离子电池电解液研究中的应用

锂离子电池在电子产品、电网存储和电动汽车等领域有着广泛的应用。电解液作为锂离子电池的重要成分,在存储和使用的过程中会发生降解,从而导致电池的寿命降低。对电解液的分析一直都是锂离子电池研究领域的重点。气相色谱法作为分离分析挥发性有机物的有利工具,在电解液的研究中发挥着重要的作用。本文综述了气相色谱法在锂离子电池电解液分析研究中的应用,包括样品的前处理、色谱柱和检测器的选择。最后对未来的研究进行了展望。     

锂离子电池及其电解液

概述了锂离子电池与传统的镍镉（Ni/Cd）、镍氢（Ni/MH)电池性能的比较，着重论述了锂离子电池电解液中的导电锂盐和有机溶剂，并介绍了锂离子电池工业的现状和对前景的展望。     

离子液体基锂离子电池电解液的应用与性能改进

近年来锂离子电池在动力电池方面被寄予厚望,但安全性是制约其应用的关键之一,而其安全性与电解液性质密切相关。离子液体具有不可燃、不挥发、热稳定性好等优点,可作为电解液以替代传统有机溶剂应用于锂离子电池中。基于现有研究,本文阐述了各类离子液体作为锂离子电池电解液的优异性和不足点,进而综述了各种针对离子液体自身不足采取的性能改进方法,并对该方向的进一步研究进行了展望。     

有机电解液在锂离子电池中的充放电机理

讨论了锂离子电池充放电过程中有机电解液的电化学行为,研究发现,有机电解液会在电极活性材料表面发生电化学反应而形成聚合物钝化层(SEI膜),其厚度和疏密性与电解液的组成及充放电制度有关;其组成和电化学性能还将直接影响锂离子电池的充放电容量和循环寿命。通过改变电解液的导电锂盐成分、有机溶剂组成和加入极性添加剂等方法可优化电解液的电化学特性,从而可有效控制该钝化层的成膜过程、膜组成与膜结构,提高锂离子电池的充放电及循环性能。     

离子液体作为电解液添加剂用于高压锂离子电池

合成了功能化离子液体1-丁基-3-甲基咪唑双（三氟甲磺酰）亚胺盐（BMIMTFSI）作为高压锂离子电池电解液添加剂,用于抑制有机溶剂的氧化,以提高碳酸酯类电解液的耐高压性。分别采用充放电测试、电化学交流阻抗（EIS）、循环伏安法（CV）和扫描电子显微镜（SEM）等研究了LiNi_0.5Mn_1.5O₄/Li电池的电化学行为和LiNi_0.5Mn_1.5O₄材料表面形貌。结果表明,当在电解液中添加20% （体积分数）BMIMTFSI时,LiNi_0.5Mn_1.5O₄/Li电池在室温、0.2C下的最高放电比容量是126.81 mA·h·g^-1,5C下的放电比容量为109.36 mA·h·g^-1,比在1 mol·L^-1 LiPF₆-EC/DMC电解液中的放电比容量提高了91.7%;且该电池在0.2C下循环50圈后的放电比容量保持率在95%左右,比用碳酸酯类电解液提高了近10%。SEM结果表明,在碳酸酯类电解液中加入BMIMTFSI后,LiNi_0.5Mn_1.5O₄电极表面附着了一层均匀且致密的固态电解质界面（SEI）膜。     

锂离子二次电池电解液研究进展

电解液是锂离子电池的重要组成部分,对电池的许多性能如循环性能、安全性能等有着重要的影响。对近年来国内外涉及电解质盐及有机溶剂的最新研究成果进行了总结和分析。从电解液材料和电解液添加剂的阻燃性能两个角度对锂离子电池材料的安全性能研究进展进行综述,介绍了辅助溶剂的改良和阻燃添加剂的研究状况。     

锂离子电池电解液含磷阻燃剂的研究进展

锂离子电池以其独特的优势在各领域应用广泛,但安全问题一直困扰着其向大容量动力电池方向发展。本文总结了近几年为增强锂离子电池的安全性,对锂离子电池电解液所做的阻燃处理,重点对含磷阻燃剂进行归类,并对含磷阻燃剂的应用发展进行展望。     

锂离子电池新型电解液的研究进展

电解液作为锂离子电池的关键材料之一,其在正、负极之间起到传递离子的作用。近年来新型电解液的研究备受关注,主要对高电压电解液、超低温电解液、阻燃电解液和聚合物电解质等4方面进行了简要综述。     

顺酐液相加氢制备丁二酸酐

一步法顺酐加氢生产丁二酸酐的最佳条件为:加氢压力1~1.6 MPa,反应温度50~100℃,反应时间1~2 h,骨架镍催化剂用量是顺酐用量的4%~6%,搅拌速度300 r/m in,在此条件,丁二酸酐的最高收率可达90%以上。     

Gel electrolyte for lithium-ion batteries

The electrochemical performance of gel electrolytes based on crosslinked poly[ethyleneoxide-co-2-(2-methoxyethyoxy)ethyl glycidyl ether-co-allyl glycidyl ether] was investigated using graphite/Li_1.1[Ni_1/3Mn_1/3Co_1/3]_0.9O₂ lithium-ion cells. It was found that the conductivity of the crosslinked gel electrolytes was as high as 5.9 mS/cm at room temperature, which is very similar to that of the conventional organic carbonate liquid electrolytes. Moreover, the capacity retention of lithium-ion cells comprising gel electrolytes was also similar to that of cells with conventional electrolytes. Despite of the high conductivity of the gel electrolytes, the rate capability of lithium-ion cells comprising gel electrolytes is inferior to that of the conventional cells. The difference was believed to be caused by the poor wettability of gel electrolytes on the electrode surfaces.     

丁二酸酐生产技术及其研究进展

丁二酸酐(SA)由于其独特的二元羧酸酐结构,可用于合成多种精细化工产品,被广泛应用各种领域。综述了不同原料的生产工艺如顺酐(MA)法、丁二酸脱水法、生物发酵法等,分析了不同的合成方法之利弊。重点论述了以顺酐为原料的生产工艺的技术进展,并对顺酐催化加氢合成丁二酸酐催化剂研究进展及工程化放大情况进行了阐述。结合国内丁二酸酐生产现状,认为顺酐液相加氢连续化生产丁二酸酐是工业化发展的主流方向。     

Effects of copper trifluoromethanesulphonate as an additive to propylene carbonate-based electrolyte for lithium-ion batteries

Addition of copper trifluoromethanesulphonate (CuTF) to propylene carbonate (PC)-based electrolyte effectively suppresses the cointercalation and decomposition of PC in the mesocarbon microbeads (MCMB) electrodes during the first lithiation process. During the first charging cycle, copper ions are reduced at a higher potential (2 V versus Li/Li⁺) than the potential of PC cointercalation and decomposition (0.6-0.8 V versus Li/Li⁺), and predominately form a porous copper layer over the MCMB surface, thereby obstructing PC to cointercalate. An increase in reversible capacity can be achieved by increasing the amount of CuTF. However, above a critical value, the copper layer inhibits the intercalation of lithium ions and lowers the capacity. The AC impedance data reveal that the passivation film and the charge-transfer resistance are both increased when the deposited copper is in excess. An optimum result may be obtained when the addition is approximately 5 wt.%. CuTF is a possibility for PC-based electrolyte additive in lithium-ion batteries.     

聚异丁烯丁二酸酐中聚异丁烯的液相色谱分析

利用高效液相色谱,采用外标法测定聚异丁烯丁二酸酐中间产品中聚异丁烯的含量,采用示差检测器进行检测。色谱柱为自制改性氧化铝柱（4.6mm×250mm,15.0μm）,正己烷为流动相,流速为1mL/min。标准曲线相关性良好,聚异丁烯平均线性范围为3.8-111g/L,其线性相关系数为0.9998,相对标准偏差为2.08%,回收率为98.5%-101.5%。该方法简便、经济、结果准确。     

热合法聚异丁烯丁二酸酐制备工艺研究

以高活性聚异丁烯(PIB)和马来酸酐(MA)为原料,采用直接加热法制备了聚异丁烯丁二酸酐。试验考察了反应添加剂、反应温度、反应时间、原料配比对产物酸值的影响。确定的最佳工艺条件为:不添加任何添加剂、反应温度200℃,反应时间7 h,n(MA)/n(PIB)为2.3。该工艺条件下得到的产物为褐红色透明黏稠液体,产物酸值(以KOH计)达到90.8 mg/g。     

High flash point electrolyte for use in lithium-ion batteries

The high flash point solvent adiponitrile (ADN) was investigated as co-solvent with ethylene carbonate (EC) for use as lithium-ion battery electrolyte. The flash point of this solvent mixture was more than 110 °C higher than that of conventional electrolyte solutions involving volatile linear carbonate components, such as diethyl carbonate (DEC) or dimethyl carbonate (DMC). The electrolyte based on EC:ADN (1:1 wt) with lithium tetrafluoroborate (LiBF₄) displayed a conductivity of 2.6 mS cm⁻¹ and no aluminum corrosion. In addition, it showed higher anodic stability on a Pt electrode than the standard electrolyte 1 M lithium hexafluorophosphate (LiPF₆) in EC:DEC (3:7 wt). Graphite/Li half cells using this electrolyte showed excellent rate capability up to 5C and good cycling stability (more than 98% capacity retention after 50 cycles at 1C). Additionally, the electrolyte was investigated in NCM/Li half cells. The cells were able to reach a capacity of 104 mAh g⁻¹ at 5C and capacity retention of more than 97% after 50 cycles. These results show that an electrolyte with a considerably increased flash point with respect to common electrolyte systems comprising linear carbonates, could be realized without any negative effects on the electrochemical performance in Li-half cells.     

高安全性三甲基硅功能化碳酸丙烯酯电解液的合成及其在锂离子电池中的应用

设计合成了一种新型三甲基硅取代碳酸丙烯酯化合物(TMSPC),并对其化学结构、热性能、离子电导率、电化学窗口和燃烧性能进行了详细的表征。通过与商业电解液(1 mol·L^-1 LiPF₆/EC:DEC=1:1,体积比)互配组成电解液,30%(vol) TMSPC的添加能大大降低电解液的燃烧速率。同时,对LiFeO₄/Li半电池进行测试,在0.2 C倍率条件下,30%(vol) TMSPC的添加也能提高电池的循环性,未添加与添加TMSPC的LiFeO₄/Li 在110个循环后的容量分别为106 mA·h·g^-1和109 mA·h·g^-1,相应的容量保持率为81%和87%。     

Solid‐state grafting of succinic anhydride onto poly(vinyl alcohol)

The graft reaction of succinic anhydride onto poly(vinyl alcohol) (PVA) was catalyzed by p‐toluenesulfonic acid monohydrate in solid state. The infrared spectra and ¹H‐NMR spectra confirmed that succinic anhydride was successfully grafted onto PVA backbone. The influences of reaction temperature, reaction time, the amount of succinic anhydride, and the amount of catalyst on the graft reaction were studied. Uncrosslinked PVA graft copolymer with grafting degree up to about 6.5% could be obtained under low reaction temperature, short reaction time, and low amount of catalyst, whereas crosslinked PVA with high gel content could be obtained under high reaction temperature, long reaction time, and high amount of catalyst. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 848–852, 2007