侧挂聚醚和烷基磺酸锂的单离子梳状聚合物电解质的合成与性能

采用α 烯丙基聚醚(UPEO)/烯丙基磺酸锂(LS)/苯乙烯(St)共聚反应,合成得到一种以聚烯烃链为主链、侧挂聚醚和烷基磺酸锂的新型单离子梳状聚合物电解质(CPPL)。通过元素分析、IR、GPC以及DSC等对其结构与形态进行了分析表征。研究了反应物料配比、催化剂、反应时间等因素对CPPL物理性能的影响。研究结果表明:该类聚合物电解质膜材料的θg值和成膜性能主要取决于单体原料配比,CPPL室温电导率可达9.3×10-3s/cm。     

梳状聚合物PAALi-g-PEO的合成与表征

采用大分子单体法设计并合成出非晶态的标题化合物,利用红外光谱和核磁共振氢谱对产物进行结构表征,利用差示扫描量热法(DSC)测定产物的玻璃化转变温度(Tg)和结晶度,并研究了原料和配比对产物的影响。结果表明,所合成的梳状共聚物PAALi-g-PEO为非晶态,其Tg在-54℃左右;当以MPEG-600为原料,EO/AALi=4时,产物适宜作为聚合物电解质基体。     

新型多巴基生物可降解梳状聚合物的合成及性能研究

以3,4-二羟基苯丙氨酸(DOPA)作为生物基单体,通过对酚羟基保护、缩聚、脱保护,得到聚多巴PDOPA;以PDOPA为大分子引发剂,用酚羟基引发丙交酯(乳酸二聚体)开环聚合,制备具有梳状结构的接枝聚合物——聚多巴-g-聚乳酸(PDOPA-g-PLA)。用凝胶渗透色谱仪、光学接触角仪、差示扫描量热仪、热失重分析仪和万能试验拉力机等考察了所得共聚物的分子量、热性能、表面浸润性、力学性能及降解性等性能。结果表明,PDOPA-g-PLA具有较好的溶解性、热稳定性和力学性能,并且具有一定的降解性。     

梳状聚合物二醇的结构与流变性能关系

制备了一系列支链结构不同的梳状聚合物二元醇(CPD),并用FTIR对其结构进行了表征。着重研究了CPD梳状支链结构和温度对其流变性能的影响,并测定了CPD的流动活化能ΔE_η0。研究发现,梳状支链的长度增加和极性增大,CPD的黏度增加,出现剪切变稀行为的剪切速率降低。CPD的η-γ曲线出现两次剪切变稀行为,在两次行为之间存在一平台,这一平台随温度增加向高剪切速率方向移动,并逐渐变短,最后在50℃时消失。随梳状支链长度增加和极性增大,CPD的流动活化能ΔE_η0增加。     

全固态聚合物电解质的性能研究

聚合物电解质由于本身的优点,已成为锂离子电池研究的一个热点.聚合物电解质由聚合物、锂盐及添加剂组成,本文综述了聚合物电解质研究的新体系,论述了聚合物电解质中各组分对其性能的影响.     

增塑剂对聚氨酯型固体电解质离子导电性能的影响

利用溶液聚合方法合成了聚醚聚氨酯,并以聚氨酯、高氯酸锂和增塑剂为组分,制备了一系列新型聚合物固体电解质。运用差示扫描量热分析、动态力学分析、交流复阻抗谱、扫描电镜和原子力显微镜对体系性能和形态进行了研究。结果表明,在聚氨酯/高氯酸锂复合物中,增塑剂的加人会导致体系玻璃化转变温度和力学性能有所下降,离子导电性能显著增加。在所研究的6种增塑剂碳酸丙烯酯、碳酸二乙酯、二乙二醇二甲醚、N,N-二甲基甲酰胺、聚乙二醇400和丙三醇中,聚乙二醇400对聚氨酯/高氯酸锂复合物的增塑效果最好,该体系室温电导率达到10-4S／cm。     

一种嵌段星形凝胶聚合物电解质的制备与性能

将二-乙二醇甲基丙烯酸酯嵌入多羟基醇的烯酸酯中,制备嵌段星形凝胶聚合物电解质,用循环伏安、交流阻抗、X射线衍射等研究电解质和聚合物电池的性质。结果表明,二-乙二醇甲基丙烯酸酯的嵌入可明显改善凝胶的性能,获得的电解质黏性好,室温电导率为1.89mS/cm,单体用量少;以此制备的聚合物电池界面阻抗为110Ω,50次循环后容量保持率达到96%,倍率放电能力优良。二-乙二醇甲基丙烯酸酯的嵌入扩展了聚合物链间的空间,降低了分子的规整性,减小了离子迁移活化能。     

二氧化硅负载梳状聚醚三相催化剂的合成及其催化性能研究

以表面经偶联剂修饰的二氧化硅为载体,通过聚(β-氯乙基缩水甘油醚)和醇钠反应,合成了两种梳状聚醚三相转移催化剂,研究了它们在碘代、二氯卡宾对双键加成和混合醚制备反应中的催化活性.结果表明,这类催化剂具有良好的催化活性和重复使用性能.     

一种新型梳状聚醚破乳剂的合成、 改性及性能评价

我国的大部分油田当前正处于第三次采油阶段,原油产量减少,含水率增加,开采难度增高,而且在开采过程中由于受到多重因素的影响,原油乳化现象严重,需要进行破乳脱水处理。但是在原油脱水过程中,随着大量化学药剂的使用,油水中间过渡层越来越厚,因此针对油水中间过渡层,在实验室内将异戊烯醇与环氧乙烷(EO)、环氧丙烷(PO)聚合研发出一种新型高效的能够有效抑制或破坏油水中间过渡层破乳剂,并通过实验选出了效果比较好的1种破乳剂。     

Sol-gel preparation of a di-ureasil electrolyte doped with lithium perchlorate

Solid polymer electrolytes (SPEs) synthesized by the sol-gel process and designated as di-ureasils have been prepared through the incorporation of lithium perchlorate, LiClO₄, into the d-U(2000) organic-inorganic hybrid network. Electrolytes with lithium salt compositions of n (where n indicates the number of oxyethylene units per Li⁺ ion) between ∞ and 0.5 were characterized by conductivity measurements, cyclic voltammetry at a gold microelectrode, thermal analysis and Fourier transform Raman (FT-Raman) spectroscopy. The conductivity results obtained suggest that this system offers a quite significant improvement over previously characterized analogues doped with lithium triflate [S.C. Nunes, V. de Zea Bermudez, D. Ostrovskii, M.M. Silva, S. Barros, M.J. Smith, R.A. Sá Ferreira, L.D. Carlos, J. Rocha, E. Morales, J. Electrochem. Soc. 152 (2) (2005), A429]. “Free” perchlorate ions, detected in all the samples examined, are identified as the main charge carriers in the sample that yields the highest room temperature conductivity (n = 20). In the di-ureasils with n ≤ 10 ionic association is favoured and the ionic conductivity drops.     

The effect of different lithium salts on conductivity of comb-like polymer electrolyte with chelating functional group

The behaviors of lithium ions in a comb-like polymer electrolyte with chelating functional group complexed with LiCF₃SO₃, LiBr and LiClO₄ were characterized by differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) spectroscopy, AC impedance, and ¹³C solid-state NMR measurement. The comb-like copolymer was synthesized from poly(ethylene glycol) methyl ether methacrylate (PEGMEM) and (2-methylacrylic acid 3-(bis-carboxymethylamino)-2-hydroxy-propyl ester) (GMA-IDA). FT-IR spectra reveal the interactions of Li⁺ ions with both the ether oxygen of the PEGMEM and the nitrogen atom of the GMA-IDA segments. FT-IR spectra also indicate an increasing anion-cation association consistent with increasing LiCF₃SO₃ concentrations. Moreover, the ¹³C solid-state NMR spectra for the carbons attached to the ether oxygen atoms exhibited significant line broadening and a slight upfield chemical shift when the dopant was added to the polymer. These findings indicate coordination between the Li cation and the ether oxygens in the PEG segment. T_g and T_d of copolymers doped with salts clearly increase, as shown by DSC and TGA measurements. These results indicate the interactions of Li⁺ with both PEGMEM and GMA-IDA segments form transient cross-links inside the copolymers. The Vogel-Tamman-Fulcher (VTF)-like behavior of conductivity implies the coupling of the charge carriers with the segmental motion of the polymer chain in this study. The maximum conductivity of copolymers relates to the composition of the copolymers and the concentration of doping lithium ions. In summary, the GMA-IDA unit in the copolymer promotes the dissociation of the lithium salt, the mechanical strength and the conductivity of the polyelectrolyte.     

Studies on comb-like polymer electrolyte with a nitrile group

The behavior of lithium ions in a comb-like polymer electrolyte with a nitrile group has been characterized by differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), ac impedance, Fourier transform infrared (FTIR) spectroscopy, and solid-state NMR measurements. The comb-like copolymer is synthesized by poly(ethylene glycol-methyl ether methacrylate) (PEGMEM) and acrylonitrile (AN). FTIR spectra reveal the interactions of Li⁺ ions with both the ether oxygen of the PEGMEM and the nitrogen atom of the AN segments. solid-state NMR spectra demonstrate the interactions of Li⁺ ions with both the ether oxygen of the PEGMEM and the nitrogen atom of the AN segments. Moreover, solid-state NMR shows that the lithium ions are preferentially coordinated to the PEGMEM segment. The T_g increases for the copolymers doped with LiClO₄. These results indicate the interactions of Li⁺ with both PEGMEM and AN segments form transient cross-links. The dependence of the maximum conductivity on the doping lithium ion concentration was determined. The AN unit in the copolymer improves the dissociation of the lithium salt, and the mechanical strength.     

The environment of lithium ions and conductivity of comb-like polymer electrolyte with a chelating functional group

The behavior of lithium ions in a comb-like polymer electrolyte with a chelating functional group have been characterized by differential scanning calorimeter (DSC), dynamic mechanical analysis (DMA), Fourier transform infrared (FTIR) spectroscopy, ac impedance and ⁷Li solid-state NMR measurements. The comb-like copolymer is synthesized by poly(ethylene glycol-methyl ether methacrylate) (PEGMEM) and (2-methylacrylic acid 3-(bis-carboxymethylamino) -2-hydroxy-propyl ester) (GMA-IDA). FTIR and ⁷Li solid-state NMR spectra demonstrate the interactions of Li⁺ ions with both the ether oxygen of the PEGMEM and the nitrogen atom of the GMA-IDA segments. Moreover, ⁷Li solid-state NMR shows that the lithium ions are preferentially coordinated to the GMA-IDA segment. The T_g increases for the copolymers doped with LiClO₄. These results indicate the interactions of Li⁺ with both PEGMEM and GMA-IDA segments form transient cross-links. The Vogel-Tamman-Fulcher (VTF)-like behavior of conductivity implies the coupling of the charge carriers with the segmental motion of the polymer chains. The dependence of the maximum conductivity on the composition of the copolymers and the doping lithium ion concentration was determined. The GMA-IDA unit in the copolymer improves the dissociation of the lithium salt, the mechanical strength and the conductivity.     

Effects of the surface treatment of the Al2O3 filler on the lithium electrode/solid polymer electrolyte interface properties

The lithium deposition-dissolution process in solid polymer electrolytes containing Al₂O₃ filler treated under different conditions has been investigated comparing with the ionic conduction behavior of the electrolyte. The composite electrolytes were prepared from poly(ethylene oxide) (PEO), LiBF₄ and α-Al₂O₃ filler by using a dry process, where the surface of α-Al₂O₃ was beforehand modified by a wet process. The exchange current densities, i₀, of the lithium electrode process in P(EO)₂₀LiBF₄ with and without Al₂O₃ filler were determined by a micro-polarization method. The temperature dependence of i₀ provided similar values for activation energy, ca. 25 and 70 kJ mol⁻¹ in both temperature regions above and below 60 °C, respectively. The effect of the surface treatment of the filler on the lithium electrode process gave a different tendency from that on the ionic conductivity. The Al₂O₃ surface treated by alkali solution enhanced the electrode process to the largest extent among the fillers used here, while it led to rather poor cycling stability in voltammetry. The enhanced reaction rate at the lithium electrode/solid polymer electrolyte interface has probably resulted in the improved ion dissociation by the surface groups of the Al₂O₃ filler.     

制备锂电池电解质六氟磷酸锂的工艺探讨

分析了目前国内外锂电池的发展状况,并对其中一种电解质六氟磷酸锂的制备工艺作了一些探讨。简要介绍了国外已经研究出的六氟磷酸锂的替代产品———氟烷基磷酸锂用作锂电池电解质。     

凝胶聚合物电解质在锂硫电池中的应用状况

从凝胶聚合物电解质的制备方法 (原位聚合法和溶液浇铸法)出发,对锂硫电池中凝胶聚合物电解质的应用展开了探究。     

The conductivity and characterization of the plasticized polymer electrolyte based on the P(AN-co-GMA-IDA) copolymer with chelating group (II): The effect of free ion in the plasticized polymer electrolyte

A new gel-type polymer electrolyte (GPE) was made by the copolymerizing acrylonitrile (AN) and (2-methylacrylic acid 3-(bis-carboxymethylamino)-2-hydroxy-propyl ester) (GMA-IDA). The copolymer mixed with a plasticizer—propylene carbonate (PC) and lithium salt to form GPE. The lithium salts are LiCF₃SO₃, LiBr and LiClO₄. FT-IR spectra show that the lithium ion in the LiClO₄ system has the strongest interaction with the group based on the plasticized polymer. FT-IR spectra also indicate that CF₃SO₃⁻ prefers producing anion-cation association. Moreover, the ¹³C solid state NMR spectra for the carbons attached to the PC of GPE exhibited different level of chemical shift (158.5 ppm) when the different lithium salts were added to the electrolyte. The results of differential scanning calorimeter (DSC) also indicate that the LiClO₄ system has more free lithium ions; therefore, it has the maximum conductivity. In this study, the highest conductivity 2.98 × 10⁻³ S cm⁻¹ exists in AG2/PC = 20/80 wt.% system which contain 3 mmole (g-polymer)⁻¹ LiClO₄. Additionally, the polymer electrolytes, which contain GMA-IDA have better interfacial resistance stability with lithium electrode.     

Effect of zwitterionic salt on the electrochemical properties of a solid polymer electrolyte with high temperature stability for lithium ion batteries

In this study, we prepare a kind of solid polymer electrolyte (SPE) based on N-ethyl-N′-methyl imidazolium tetrafluoroborate (EMIBF₄), LiBF₄ and poly(vinylidene difluoride-co-hexafluoropropylene) [P(VdF-HFP)] copolymer. The resultant SPE displays high thermal stability above 300 °C and high room temperature ionic conductivity near to 10⁻³ S cm⁻¹. Its electrochemical properties are improved with incorporation of a zwitterionic salt 1-(1-methyl-3-imidazolium)propane-3-sulfonate (MIm3S). When the SPE contains 1.0 wt% of the MIm3S, it has a high ionic conductivity of 1.57 × 10⁻³ S cm⁻¹ at room temperature, the maximum lithium ions transference number of 0.36 and the minimum apparent activation energy for ions transportation of 30.9 kJ mol⁻¹. The charge-discharge performance of a Li₄Ti₅O₁₂/SPE/LiCoO₂ cell indicates the potential application of the as-prepared SPE in lithium ion batteries.     

Semi-interpenetrating gel polymer electrolyte based on PVDF-HFP for lithium ion batteries

Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)-based gel polymer electrolyte (GPE) is considered one of the promising candidate electrolytes in the polymer lithium ion battery (LIB) because of its free standing, shape versatility, security, flexibility, lightweight, reliability, and so on. However, the pristine PVDF-HFP GPE cannot still meet the requirement of large-scale LIBs and other electrochemical devices due to its relatively low ionic conductivity and deterioration of mechanical strength caused by the incorporation of organic liquid electrolyte into the polymer matrix as well as high cost. In order to overcome above deficiencies of PVDF-HFP based GPE, ultraviolet (UV)-curable semi-interpenetrating polymer network is designed and synthesized through UV-irradiation technique, and the as-prepared semi-interpenetrating matrix is constituted by pentaerythritol tetracrylate polymer network and PVDF-HFP. The ionic conductivity of the optimized GPE is as high as 5 × 10⁻⁴ S/cm and electrochemical window is up to 4.8 V at room temperature. Especially, the LIB prepared by GPE shows the high initial discharge specific capacity of 151 mAh/g at 0.5 C and good rate capability. Therefore, the semi-interpenetrating GPE based on PVDF-HFP exhibits a promising prospect for the application of rechargeable LIBs.