新型核-多臂星形聚合物电解质

采用傅里叶转换红外光谱法(FT-IR)、微分扫描量热分析(DSC)、离子阻抗谱等测试手段对以超支化聚缩水甘油(HPG)为核，线型聚氨酯(PEU)为臂的核-多臂星形聚合物进行了表征，对其分子结构与电导性能之间的关系进行了初步探索．结果表明，星形聚合物比线型聚合物有更强的溶盐能力和离子传输能力．氧锂比(氧化乙烯单元与锂离子的摩尔比)为4，共混比(质量)为30％时，体系的最高电导率可达0．2mS／cm．当星形聚合物的臂数为5时，体系的电导率高于相同条件下的其他臂数的聚合物体系．体系的电导率随温度的升高而升高，其变化规律符合Arrhcnius方程．     

Ionic conductivity in crystalline polymer electrolytes

Polymer electrolytes are the subject of intensive study, in part because of their potential use as the electrolyte in all-solid-state rechargeable lithium batteries. These materials are formed by dissolving a salt (for example LiI) in a solid host polymer such as poly(ethylene oxide) (refs 2, 3, 4, 5, 6), and may be prepared as both crystalline and amorphous phases. Conductivity in polymer electrolytes has long been viewed as confined to the amorphous phase above the glass transition temperature, Tg, where polymer chain motion creates a dynamic, disordered environment that plays a critical role in facilitating ion transport. Here we show that, in contrast to this prevailing view, ionic conductivity in the static, ordered environment of the crystalline phase can be greater than that in the equivalent amorphous material above Tg. Moreover, we demonstrate that ion transport in crystalline polymer electrolytes can be dominated by the cations, whereas both ions are generally mobile in the amorphous phase. Restriction of mobility to the lithium cation is advantageous for battery applications. The realization that order can promote ion transport in polymers is interesting in the context of electronically conducting polymers, where crystallinity favours electron transport.     

锂离子电容器碳酸乙烯酯基电解液的研究

采用2种碳酸乙烯酯基电解液制作了基于活性炭正极和软碳负极的软包装锂离子电容器(LICs),研究了器件的直流内阻、倍率、阻抗和循环稳定性等电化学性能.结果表明:通过向碳酸乙烯酯(EC)和碳酸二乙酯(DEC)的混合溶剂中加入碳酸丙烯酯(PC),得到双氟磺酰亚胺锂电解液(1.2 mol/L LiFSI : (EC/PC/DEC)), 可使LICs具有更低的内阻和更佳的倍率性能,而且低温下其电化学性能亦有显著提高.研究结果对于开发低内阻和低温LICs的电解液具有重要意义.     

聚氨酯／LiCF3SO3电解质体系的导电机理

利用FT-Raman、FT-IR和复数阻抗谱,对聚氧化乙烯聚氨酯/LiCF3SO3固体电解质样品中离子在聚合物电解质中的导电机理进行了研究,发现导电离子以自由离子、离子对和聚集体的形式存在于体系中,离子状态随盐浓度不同发生变化,自由离子比率随温度的上升而下降;对离子的存在状态与电导率之间的关系进行了研究,发现体系的电导率随自由离子的比率上升而变大;初步探讨了离子在体系中的导电机理;对Nernst-Einstein公式在聚合物电解质体系的应用做了校正,建立了合理的自由离子浓度和电导率的关系。     

从盐湖卤水中萃取锂

选取磷酸三丁酯(TBP)为萃取剂,200号溶剂汽油为稀释剂,氯化铁(FeCl3.6H2O)为共萃取剂,从青海盐湖含锂卤水中萃取锂,并对TBP质量分数对萃取率的影响,相比对萃取率及分配比的影响进行研究。研究结果表明:共萃剂FeCl3在萃取过程中作用明显,同时,水相氢离子浓度是非常重要的影响因素,适当的酸度既可以保证锂离子进入有机相,减少氢离子与有机溶剂络合的机会,又可以保证铁离子在溶液中不发生水解;最佳萃取工艺条件如下:TBP质量分数为60%,萃取相比(O/A)为1.5,n(Fe3 )/n(Li )为1.3,水相氢离子浓度为0.05 mol/L。在此条件下,锂的萃取率可达到80%,锂、镁分离效果较好,萃取液经洗涤、反萃取和深度除镁后,可制备高纯度碳酸锂。     

苯甲酸锂、对本二酸锂及均苯三甲酸锂的电化学性能

与传统的锂离子电池（LIBs）无机材料相比,有机电极材料因具有理论容量高、可再生、成本低、环境友好等优点已成为LIBs电极材料的热门研究方向. 然而有机材料易溶解在有机电解液中,阻碍有机电极材料的进一步市场化.本文通过含不同数量羧酸的苯甲酸、对苯二甲酸、均苯三甲酸分别与氢氧化锂进行简单中和反应生成相应的苯甲酸锂、对苯二甲酸锂、均苯三甲酸锂,作为有机负极嵌锂材料,并研究不同数量的羧基锂基团对这三种电极材料电化学性能的影响.研究结果显示苯甲酸锂、对苯二甲酸锂、均苯三甲酸锂电极材料在0.1C电流倍率下首次放电容量分别为~250、~340、~268 mAh g-1,50次循环后,其放电容量分别为~75、~100、~60 mAh g-1,表明对苯二甲酸锂电极材料循环前后放电容量最高.通过溶解性实验表明对苯二甲酸锂是最难溶解在有机电解液中.对苯二甲酸锂能够通过O-LiO-键作用形成二维大分子链的结构,能有效抑制溶解.从以上实验结果看出,对苯二甲酸锂电极材料是最有希望的LIBs有机负极材料.     

聚酯及其电解质的热稳定性

以酯交换反应合成了聚丁二酸酯系列,与高氯酸锂制成固体电解质。通过对聚酯及其电解质的热失重分析,将其热分解进行了动力学处理,结果表明这一系列聚酯分解温度相近,与链节单元长度无关;聚酯电解质的热稳定性比聚酯差,且随无机盐含量提高而降低。利用色-质谱联用技术,剖析了聚酯及其固体电解质的分解产物,提出了它们各自的分解机理。     

Increasing the conductivity of crystalline polymer electrolytes

Polymer electrolytes consist of salts dissolved in polymers (for example, polyethylene oxide, PEO), and represent a unique class of solid coordination compounds. They have potential applications in a diverse range of all-solid-state devices, such as rechargeable lithium batteries, flexible electrochromic displays and smart windows. For 30 years, attention was focused on amorphous polymer electrolytes in the belief that crystalline polymer:salt complexes were insulators. This view has been overturned recently by demonstrating ionic conductivity in the crystalline complexes PEO6:LiXF6 (X = P, As, Sb); however, the conductivities were relatively low. Here we demonstrate an increase of 1.5 orders of magnitude in the conductivity of these materials by replacing a small proportion of the XF6- anions in the crystal structure with isovalent N(SO2CF3)2- ions. We suggest that the larger and more irregularly shaped anions disrupt the potential around the Li+ ions, thus enhancing the ionic conductivity in a manner somewhat analogous to the AgBr(1-x)I(x) ionic conductors. The demonstration that doping strategies can enhance the conductivity of crystalline polymer electrolytes represents a significant advance towards the technological exploitation of such materials.     

凝胶型聚合物电解质电化学性质的研究

研究了以ＰＶＣ和ＰＭＭＡ为基的锂盐复合物凝胶电解质的电化学性质,结果表明,这些电解质具有高的离子电导率和宽的电化学稳定区,但用于二次锂电池时,会因锂电极界面被逐渐腐蚀而影响电池寿命。     

Effects of Electrolytes on the Oxidation of Carbon Fibres

Effects of electrolytes on the oxidation of carbon fibreswere investigated by ion chromatography and cyclic vol-tammogram measurement.The results indicate that theconcentration of nitrate ion decreases with increase oftreatment time,and the concentration of phosphate ionkeeps a constant in the process of electrochemical oxida-tion.Nitrate ions have more effective electrochemical ox-idation ability than other anions.The mechanism of elec-trochemical oxidation of carbon fibres was suggested.     

拉果错湖水5℃蒸发析盐规律研究

针对西藏拉果错湖水,研究5℃恒温蒸发过程析盐规律,获得蒸发过程液相中各元素的富集行为和盐类析出规律,并参考Na+、K+//Cl-、24SO-–H2O四元水盐体系相图对结果进行分析,为以后该盐湖的合理开发利用提供基础实验数据.同时蒸发剩余卤水中Li+的质量浓度由初始0.281,g/L增加为4.938,g/L,形成了很好的提锂原料.     

聚氨酯／超支化聚醚／碱金属复合体系及其离子导电性

为了进一步提高聚氨酯/盐复合体系的离子电导率,合成了聚氧化乙烯聚氨酯（PEU）和超支化聚缩水甘油（HPG）,并与高氯酸锂掺杂得到聚氨酯固体电解质,样品成膜后利用红外光谱、DSC和复阻抗谱分析进行了表征,红外分析发现,随氧锂原子比[EO]/[Li]的减小,醚氧键的吸收峰发生红移、高氯酸根谱带则向高频方向移动、DSC和复阻抗谱分析表明该体系是非晶相材料,HPG的加入提高了聚氨酯体系的电导率,室温（20℃）下,[EO]/[Li]=4～6时其最佳电导率σ达到8.5μS/cm,该体系温度和电导率的关系既不完全符合Arrhenius方程,也不完全符合VTF方程,而是呈现为复杂的曲线关系,这可能与HPG的加入有关。     

聚氨酯固体电解质的聚合物—离子相互作用及其导电作用

制备了一种结构类似于聚氨酯硬段的模型化合物,并以该模型化合物与聚氨酯和高氨酸钠盐复合,制备了一系列的聚氨酯型聚合物固体电解质,通过红外光谱和复阻抗谱分析方法对该体系的离子聚集形态、离子-聚合物相互作用进行了初步的探索,并对其离子导电性能进行了研究,结果表明,随着钠离子浓度的增加,钠离子优先与醚氧基发生络合,当其浓度达到较高水平后,转而主要与羰基发生络合;体系中盐浓度升高,自由离子和离子聚集体数目均有增加,该体系存在最佳盐程度,此时具有很高的离子导电性能,但电导率与温度关系不符合Arrhenius方程,硬段模型化合物的加入不利于体系的离子导电性能。     

Novel Amphiphilic Polymer Gel Electrolytes Based on PEG-b-GMA-co-MMA

1 Results Gel polymer electrolytes for lithium battery have been widely investigated recently because of their high ion conductivity at room temperature. We synthesized and characterized novel gel electrolytes based on amphiphilic copolymethacrylates containing different lengths of ethylene oxide (EO) chain as ionophilic units and methyl methacrylate (MMA) chain as ionophobic units[1]. Their electrochemical properties were also measured.1H NMR and FTIR analysis results elucidated that PEG-b-glycidyl met...     

Electrochemical behavior of aluminum foil in 1-alkyl-3-methylimidazolium tetrafluoroborate ionic liquids electrolytes

Aluminum (Al) foil is widely used as a current collector in lithium ion batteries, EDLCs and other electrochemical devices, and its electrochemical behavior in electrolytes has great effect on the cycle performances and safety of the electrochemical devices. In this work, corrosion behavior of Al foil in 1-alkyl-3-methylimidazolium tetrafluoroborate ionic liquids and its electrolytes containing LiTFSI as salt were studied using cyclic voltammogram method. It was found that a passive film was firmly formed on the surface of Al foil after the anodic polarization in BMI-BF_4 compared to those in EMI-BF_4 and PMI-BF_4. In addition, anodic polarization research showed that the passive film on Al surface in BMI-TFSI did not well exist. A good passive film formed on the surface of Al foil in BMI-BF_4 was not broken down until the potential was up to 94.58 V. Moreover, EDX and XPS analysis showed that F and O exist on the Al surface after the anodic polarization in BMI-BF_4, which ind-cated that a passive film like AlF3 and Al2O3 may be formed on its surface.     

锂离子电池的关键材料及其发展

锂离子电池的发展与其负极材料、正极材料和电解质材料的发展相关。本文对锂离子电池的关键材料及其发展进行阐述,以便能够更好的研究和改善电池的性能。     

铜阳极膜导电性转型起因探讨

对在不同酸碱度和添加剂的电解液中,铜电极氧化膜呈现与块体铜氧化物不同的ｎ型半导体性质的实验结果进行了综合分析,指出铜阳极膜导电性转型应归因于隙间铜离子在膜中向溶液方向的迁移并形成浓度梯度,使邻近基底的氧化物层转呈ｎ型导电,并在可吸收到足够强度和能量的照射光时呈现阳极光电流响应。     

盐湖提锂工艺——高镁锂比盐湖锂盐吸附剂研发进展

 据2019年美国地质调查局统计全球已查明锂资源量6200万t,其中59%锂资源分布在盐湖中,而绝大部分盐湖为高镁锂比盐湖,高镁锂比盐湖中锂的提取工艺更难,吸附剂可以一步直接提锂,研发循环性能高、稳定性强、制备高效的高镁锂比盐湖锂盐吸附剂迫在眉睫。根据吸附剂的制备材料和吸附机理不同,将现有吸附剂进行分类,总结了离子筛吸附剂、铝盐吸附剂、天然矿物改性吸附剂发展现状及吸附流程。对比研究发现,天然矿物改性吸附剂具有离子筛吸附剂和铝盐吸附剂提锂的所有优势,制备简单不产生废料,经济、环保、高效,在未来高镁锂比盐湖提锂工艺中应予以重点关注。     

钠离子电池电解质的研究进展

相比锂离子电池来说,钠离子电池因高能量密度和低成本引起广泛关注。作为电池重要组成部分的电解质,对电池性能的发挥至关重要。简要介绍了液、固态电解质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、电性能、电化学性能、热稳定性等特点。现今钠离子电池大多使用的是液体电解液,而液体电解液在具有高离子电导率的同时,安全性仍有待改善。而固态电解质还有许多基础科学需要探索,并且需要考虑电导率、成本等因素。基于以上评述,希望对钠离子电池电解质的研究发展提供帮助。     

混凝土中几种无机相对钢筋腐蚀的影响

用CaCO3、SiO2、Al2O3和Fe2O3为原料,通过高温固相反应,分别制备了组成单一的无机相粉体C3-S2、C3-A1和C4-A1-F1,以此来模拟混凝土无机相的主要成分。这3种粉体被分别浸泡到含有氯离子的混凝土孔隙模拟溶液中。针对浸泡实验的固液共存体系,分别做了钢筋的极化曲线测试、溶液相的氯离子浓度测试以及过滤产物的XRD晶相分析。分析结果表明,无机相粉体对钢筋起到减缓腐蚀的作用;溶液相中氯离子浓度随时间的延长均呈下降趋势,其中C3-A1和C4-A1-F1粉体对自由氯离子都有很强的结合能力;C3-A1和C4-A1-F1粉体的过滤产物中均发现了Friedel盐相(Ca2Al(OH)6Cl.2H2O),而C3-S2粉体的过滤产物中没有发现含有氯离子的产物晶体相,表明C3-A1和C4-A1-F1粉体模拟的铝酸钙(C3A)通过离子交换结合氯离子,而C3-S2粉体模拟的C-S-H凝胶相则通过物理吸附结合氯离子。