基于聚乙二醇接枝丙烯酸树酯光固化电解质的制备及性能研究

聚氧化乙烯(PEO)(聚乙二醇(PEG))和丙烯酸树脂在聚合物基电解质中具有很好的应用,本文通过紫外光引发单/双官能度的聚乙二醇接枝丙烯酸树脂单体聚合构建了离子电导率高、易于封装,可避免电解质泄漏的准固态聚合物电解质.通过调控聚乙二醇二甲基丙烯酸酯(PEGDA)和甲氧基聚乙二醇单甲基丙烯酸酯(PEGMA) 2种单体的比例以及锂盐溶液的含量,成功制备出具有高离电导率的准固态聚合物电解质.采用傅里叶变换红外光谱仪(FTIR),电化学工作站对PEGMA/PEGDA基聚合物电解质进行表征,研究各组分比例对电解质的电化学性能影响.当PEGMA/PEGDA单体比例为75/25,锂盐溶液的占比为75%时,形成的薄膜状态电解质表现出1.96×10~(-3)S·cm~(-1)的高离子电导率,较原始配比提高了14倍.将制备的电解质应用于电致变色器件,在580个变色循环后,器件依然可以实现稳定快速的颜色切换,2种颜色变换时间均在3 s以内,本文中研究的聚醚接枝丙烯酸树酯基电解质材料在电致变色器件中有较好的应用前景.     

新型梳状共聚物在准固态染料敏化太阳能电池中的应用及其对电子复合的影响

合成了乙烯基咪唑碘盐(VImI)和聚乙二醇单甲醚甲基丙烯酸酯(PEGMA)的梳状共聚物.利用VImI/PEGMA共聚物制备了准固态聚合物电解质.通过光电流密度-电压(J-V)曲线和电导率测定以及电化学阻抗分析,探讨了基于此电解质的染料敏化太阳能电池的电荷传输与界面电子转移机制.结果表明,VImI/PEGMA共聚物可以有效抑制TiO2/电解质界面电子复合并提高TiO2导带能级,敏化电池的光伏性能并不完全取决于电解质的电导率.通过考察共聚物中VImI与PEGMA单元的摩尔比与开路电压的关系,发现共聚物对电子复合的抑制作用主要源于VImI链段.此外,开路电压衰减(OCVD)和瞬态光电流测试结果说明,共聚物能够提高TiO2薄膜的电子寿命,而且对陷阱电子能级的分布具有调节作用.当共聚物在电解质中的质量分数为50%,VImI与PEGMA的摩尔比为5.0时,准固态染料敏化太阳能电池于100mW·cm-2光强下获得了4.10%的光电转换效率.     

PAN-LATP复合固态电解质的制备与性能表征

与传统的液态电解质相比,固态聚合物电解质可以显著提高锂二次电池的安全性和能量密度,但其室温锂离子传导率低、机械性能比较差,这些缺点限制了固态聚合物电解质在锂二次电池中的应用.为了解决上述问题,本文采用溶液浇铸法在聚丙烯腈(PAN)固态聚合物电解质中引入无机固态电解质Li_(1.3)Al_(0.3)Ti_(1.7)(PO_4)_3(LATP)制备了PAN-LATP复合固态电解质(CSE).该复合固态电解质不仅具有较高的锂离子电导率,还拓宽了电化学稳定窗口.当LATP含量为15%时CSE的锂离子传导率最高,室温下为2.14×10~(-5)S/cm,333 K时为3.03×10~(-4)S/cm.与此同时,固态聚合物电解质的机械强度也得到了很好的改善.结果表明该性能优良的固态电解质有望用于锂离子电池和其他电化学储能系统.     

固态聚合物电解质的锂离子传导机理与研究进展

锂离子电池(lithiumionbatteries,LIBs)在储能领域已取得了巨大的成功.然而,商用LIBs含有高挥发性易燃有机电解液,使其存在严重的安全隐患.固态聚合物电解质具有解决相应安全性问题的潜力,有望成为下一代高安全性全固态LIBs的电解质材料.然而,固态聚合物电解质存在离子电导率不高等问题,限制了其在固态LIBs中的实际应用.研究者们为了提高该类电解质的离子电导率、锂离子迁移数等综合电化学性能,已在寻找新锂盐、对聚合物进行改性以及向聚合物电解质中添加填料等方面进行了较多的研究.本文简要概述了固态聚合物电解质的锂离子传导机理以及在提高固态聚合物电解质综合电化学性能方面的研究进展.     

聚碳酸酯基固态聚合物电解质的研究进展

液态锂离子电池由于采用易泄露、易挥发、易燃烧的碳酸酯有机溶剂,在高温或极端条件下使用时,存在极大的安全隐患.使用固态电解质替代液态电解液,可以从根本上避免此类安全问题的发生,与此同时还可以大幅度提升固态锂电池的能量密度.固态电解质又分为无机固态电解质和聚合物固态电解质2大类.无机固态电解质能够在宽的温度范围内保持化学稳定性,并且电化学窗口较宽,机械强度更高,室温离子电导率较高,但脆性较大,柔韧性差,制备工艺复杂,成本较高.聚合物固态电解质,室温离子电导率偏低,难以满足室温锂离子电池的应用,但其加工成型容易,形状可变.比较而言,固态聚合物电解质,更适宜大规模生产,离产业化相对更近.固态聚合物电解质中研究较多的是聚醚基固态聚合物电解质(如聚环氧乙烷和聚环氧丙烷),但其缺点是室温离子电导率低,需要对其改性或进一步开发综合性能更加优异的其他固态聚合物电解质.聚碳酸酯基固态聚合物电解质由于其特殊的分子结构(含有强极性碳酸酯基团)以及高介电常数,可以有效减弱阴阳离子间的相互作用,提高载流子数量,从而提高离子电导率,因此被认为是一类非常有前途的固态聚合物电解质体系.基于此,本文重点综述了最近研究热点的聚碳酸酯基固态聚合物电解质,包括聚(三亚甲基碳酸酯)体系、聚(碳酸丙烯酯)体系、聚(碳酸乙烯酯)体系和聚(碳酸亚乙烯酯)体系等,并详细阐述了上述每种聚碳酸酯基固态聚合物电解质的制备、电化学性能、优缺点及改性手段,归纳出其离子配位-解配位过程和离子扩散机制,还对聚碳酸酯基固态聚合物电解质的未来发展方向和研究趋势望进行了预测和展望.     

无机-有机杂化聚合物电解质的制备与电化学性能

以有机改性聚硅氧烷为单体加入液态电解质通过紫外光辐射固化制备了无机有机杂化聚合物电解质.含有丙烯酸酯端基的有机改性聚硅氧烷单体是通过正硅酸甲酯(TMOS)的水解缩合反应产物与丙烯酸2羟乙酯(HEA)进行脱甲醇反应合成的.它是一种多官能团单体,其结构通过核磁共振氢谱(1HNMR)分析、红外光谱(FTIR)分析及二氧化硅分析进行了表征,分子式可表达为SiO1.143(OH)0.016(OCH3)1.339(OCH2CH2OCOCHCH2)0.357.无机有机杂化聚合物电解质的电化学性能通过交流阻抗和循环伏安法进行了表征.其离子电导率随着液态电解质含量的增大而提高,当液态电解质含量为85wt%时,电导率在22℃为5.5×10-3Scm-1,在-23℃也能达到1.1×10-3Scm-1.界面电阻经过开始2天的增大后达到稳定,电化学稳定窗口超过5.0V,不锈钢电极上锂的电化学沉积与剥离循环可逆性很高.     

一种高离子电导率复合聚合物电解质的简易热处理制备

固态聚合物电解质是发展柔性全固态锂离子电池的核心,但是目前室温离子电导率低限制了其应用.本研究以热聚合方法制备石墨相氮化碳(g-C_3N_4),并将其与聚氧化乙烯/高氯酸锂(PEO/LiClO_4)共混制备复合聚合物固态电解质.采用X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、光学显微镜(OM)、扫描电子显微镜(SEM)、差示扫描量热仪(DSC)和电化学工作站对复合聚合物电解质膜进行表征.结果表明,通过120℃退火-淬冷热处理及复合聚合物电解质内部的相互作用,可以较大程度抑制PEO的结晶,从而使该复合聚合物固态电解质膜的离子电导率在25℃时达到2.4×10~(-5)S cm~(-1),提高了3个数量级.     

一种双锂盐梳状聚合物电解质的制备及电化学性能

将聚乙二醇单甲醚(MPEG)接枝在聚(异丁烯-alt-马来酸酐)(PIAMA)上合成梳状锂单离子导体PIAMA-g-MPEG, 并与双(三氟甲基磺酰)亚胺锂(LiTFSI)复合制成双锂盐梳状聚合物电解质薄膜. 用核磁共振波谱 (¹H NMR)、 热重分析(TG)、 扫描电子显微镜(SEM)、 电化学阻抗(EIS)和电池充放电测试等方法对聚合物基体和电解质的物化性质和电化学性能进行了研究.结果表明, 设计的双锂盐梳状聚合物电解质能够有效解离并传输锂离子, 70 ℃下离子迁移数(t_Li⁺)为0.32, 离子电导率(σ)为1.5×10^-4 S/cm, 电化学稳定窗口为0~4.9 V (vs. Li/Li⁺). 组装Li|PIAMA-g-MPEG|Li电池并进行70 ℃恒电流充放电电压极化测试, 结果表明, 电解质与金属锂负极兼容性较好, 能够有效抑制锂枝晶的生长.组装LiFePO₄|PIAMA-g-MPEG|Li电池进行70 ℃长循环及倍率性能测试, 电解质表现出了优异的高温性能.     

新型梳状聚甲基丙烯酸酯固态聚合物电解质的制备及导电性能研究

采用溶液聚合方法,以甲基丙烯酸甲酯、聚乙二醇单甲醚甲基丙烯酸酯为共聚单体,制备一种新型无规梳状聚合物,并研究了一系列掺杂不同含量高氯酸锂全固态聚合物电解质的导电性能.FTIR、1H-NMR结果证实了新型梳状聚合物具有无规梳状结构特征.DSC和XRD结果表明了聚合物电解质主要是以无定型状态存在.SEM和FTIR结果证实了当锂盐含量低于16 wt%时,锂盐在聚合物中具有良好的溶解性,ClO4-主要以单离子状态存在,此时聚合物电解质30℃离子电导率达到最大值,为4.81×10-5S/cm.当锂盐含量超过16wt%时,Li+ClO4-离子对含量明显增多,表明了锂盐溶解性能下降,同时聚合物电解质离子电导率显著下降,这主要是锂盐增加导致离子的缔合增强,不利于离子的传导所致.     

聚环氧乙烷聚合物电解质基高电压固态锂金属电池的研究进展

采用液态碳酸酯电解质的锂离子电池在遭遇极端工况时, 极易发生泄露、燃烧、甚至爆炸等重大安全事故. 相对比, 聚环氧乙烷(PEO)固态聚合物电解质可以显著提升锂电池的安全性, 并且其优异的可塑性使其可以被制成特定形状进而满足特殊领域的差异化需求; 更为重要的是: PEO固态聚合物电解质与锂金属负极兼容性好. 然而, PEO固态聚合物电解质电化学氧化窗口低, 难以匹配高电压正极材料(≥4 V), 极大限制了其在高电压、高能量密度固态聚合物锂金属电池中的进一步应用. 近期经过国内外科研工作者在PEO固态聚合物电解质结构设计、PEO端羟基改性、含硼锂盐引入、功能型粘结剂设计开发以及正极界面层构筑等方面所做出的不懈努力, PEO固态聚合物电解质基高电压固态锂金属电池取得了系列化重大科研进展. 基于此, 本综述主要从以下八个方面: (1)高电压正极片表面修饰超薄聚合物层、(2)高电压正极颗粒包覆、(3)对碳黑颗粒进行包覆、(4)使用富含羧基的粘结剂、(5)不对称固态聚合物电解质结构设计、(6)正极界面原位形成耐高电压界面层、(7)醚氧官能团(-OCH₃)封端PEO, 提升其本征耐高电压性能、(8)含硼锂盐做添加剂, 详细综述了采用PEO固态聚合物电解质构建的高电压固态锂金属电池所取得的最新研究进展以及相应的高电压固态锂金属电池界面稳定作用机制. 最后还对未来PEO固态聚合物电解质在高电压固态锂金属电池方面所存在的巨大挑战和发展趋势进行了详细展望和总结阐述.     

聚苯并咪唑-锂盐-聚乙二醇单甲醚共混全固态聚合物电解质的制备及性能

使用共混后浇铸成膜的方法,制备了聚苯并咪唑-锂盐-聚乙二醇单甲醚组成的锂离子电池共混全固态聚合物电解质。通过傅里叶红外光谱(FT-IR)、X射线衍射(XRD)、差示扫描量热(DSC)、拉伸与交流阻抗测试表征了共混全固态电解质的结构与性能。研究了不同锂盐以及各组分含量对共混全固态电解质的力学性能与电导率的影响。结果表明:聚苯并咪唑与聚乙二醇单甲醚之间存在氢键;共混全固态电解质中聚乙二醇单甲醚处于无定形态;锂盐的加入使聚乙二醇单甲醚的玻璃化转变温度下降;聚乙二醇单甲醚含量越高,共混膜强度越低,电导率越高,并且使用三氟甲磺酸锂作为锂盐时其电导率最高,室温下可以达到3.58×10~(-5) S/cm,高温下可以达到3.3×10~(-3) S/cm,高温下满足对锂离子电池的使用需求。     

Sulfonated Poly(ether ether ketone) and Poly(ethylene glycol) Diacrylate Based Semi-Interpenetrating Network Membranes for Fuel Cells

Polymer electrolyte membranes are prepared from novel semi-interpenetrating polymer network material where the sulfonated poly (ether ether ketone) (SPEEK) is the linear polymer and the poly (ethylene glycol) diacrylate (PEGDA) is the cross-linking constituent. The semi-IPN is prepared by in situ polymerization of PEGDA in the presence of sulfonated poly (ether ether ketone). SPEEK is prepared by direct sulfonation of commercial PEEK (Gatone? 1100) by reported procedures. SPEEK with degree of sulfonation 63% (calculated from FT-NMR) is selected as the base membrane and different semi-IPN membranes were prepared by varying the PEGDA and SPEEK ratio. The degree of sulfonation of SPEEK and the formation of semi-IPN were confirmed by spectroscopy studies. The various semi-IPN membranes were characterized for ion-exchange capacity, water uptake, hydrolytic stability, proton conductivity and thermal stability for evaluating the suitability of these membranes for fuel cells. The proton conductivity of the membranes decreased with increasing PEGDA content. The Semi-IPN membranes exhibited conductivities (30°C) from 0.018 S/cm to 0.006 S/cm. These interpenetrating network membranes showed higher hydrolytic stability than the pure SPEEK membrane. This study shows that semi-IPN membranes based on PEGDA and SPEEK can be viable candidates for electrolyte membranes.     

Functionalization of hydrogen-terminated silicon via surface-initiated atom-transfer radical polymerization and derivatization of the polymer brushes

Surface-initiated atom-transfer radical polymerization (ATRP) of poly(ethylene glycol) monomethacrylate (PEGMA) was carried out on the hydrogen-terminated Si(100) substrates with surface-tethered alpha-bromoester initiator. Kinetic studies confirmed an approximately linear increase in polymer film thickness with reaction time, indicating that chain growth from the surface was a controlled "living" process. The "living" character of the surface-grafted PEGMA chains was further ascertained by the subsequent extension of these graft chains, and thus the graft layer. Well-defined polymer brushes of near 100 nm in thickness were grafted on the Si(100) surface in 8 h under ambient temperature in an aqueous medium. The hydroxyl end groups of the poly(ethylene glycol) (PEG) side chains of the grafted PEGMA polymer were derivatized into various functional groups, including chloride, amine, aldehyde, and carboxylic acid groups. The surface-functionalized silicon substrates were characterized by reflectance FT-IR spectroscopy and X-ray photoelectron spectroscopy (XPS). Covalent attachment and derivatization of the well-defined PEGMA polymer brushes can broaden considerably the functionality of single-crystal silicon surfaces.     

交联PEO嵌段共聚物固体电解质的制备及导电性研究

利用低分子聚乙二醇 (PEG ,Mn=6 0 0 )与CH2 Cl2 在碱性条件下通过Williamson反应生成氧亚甲基连接的聚氧化乙烯嵌段聚合物 .1 H NMR表明 ,其分子平均组成以 [CH2 O(CH2 CH2 O) 1 3]为重复单元结构 .适量的2 ,4 二异氰酸甲苯酯 (TDI)与聚合物 锂盐电解质形成交联网络结构 ,具有较好的成膜性能、力学性能与热稳定性能 .在测试温度范围内 ,电导率与温度的关系很好的符合Arrhenius关系式 (σ =Ae-Ea RT) .锂盐浓度不同 ,Arrhenius曲线有一个或两个活化能 (Ea)值出现 .该聚合物掺混LiN(CF3SO2 ) 2 形成的固体电解质具有良好的导电性 ,在EO Li =2 5∶1(摩尔比 )时 ,室温下σ =1 12× 10 - 5S cm ,分解电压可达 5 0V .     

PREPARATION OF STAR NETWORK PEG-BASED GEL POLYMER ELECTROLYTES FOR ELECTROCHROMIC DEVICES

An amorphous,colorless,and highly transparent star network polymer with a pentaerythritol core linking four PEG-block polymeric arms was synthesized from the poly(ethylene glycol)(PEG),pentaerythritol,and dichloromethane by Williamson reaction.FTIR and ~1H-NMR measurement demonstrated that the polymer repeating units were C[CH_2-OCH_2O-(CH_2CH_2O)_m-CH_2O-(CH_2CH_2O)_n-CH_2O]_4.The polymer host held well mechanical properties for pentaerythritol cross-linking.The gel polymer electrolytes based on Lithium...     

High ionic conductivity P(VDF-TrFE)/PEO blended polymer electrolytes for solid electrochromic devices

Solid polymer electrolytes with excellent ionic conductivity (above 10(-4) S cm(-1)), which result in high optical modulation for solid electrochromic (EC) devices are presented. The combination of a polar host matrix poly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE) and a solid plasticized of a low molecular weight poly(ethylene oxide) (PEO) (M(w)≤ 20,000) blended polymer electrolyte serves to enhance both the dissolution of lithium salt and the ionic transport. Calorimetric measurement shows a reduced crystallization due to a better intermixing of the polymers with small molecular weight PEO. Vibrational spectroscopy identifies the presence of free ions and ion pairs in the electrolytes with PEO of M(w)≤ 8000. The ionic dissolution is improved using PEO as a plasticizer when compared to liquid propylene carbonate, evidently shown in the transference number analysis. Ionic transport follows the Arrhenius equation with a low activation energy (0.16-0.2 eV), leading to high ionic conductivities. Solid electrochromic devices fabricated with the blended P(VDF-TrFE)/PEO electrolytes and polyaniline show good spectroelectrochemical performance in the visible (300-800 nm) and near-infrared (0.9-2.4 μm) regions with a modulation up to 60% and fast switching speed of below 20 seconds. The successful introduction of the solid polymer electrolytes with its best harnessed qualities helps to expedite the application of various electrochemical devices.     

Influence of PEG-borate ester on thermal property and ionic conductivity of the polymer electrolyte

We have focused on the poly(ethylene glycol) (PEG)-borate ester as a new type plasticizer for solid polymer electrolyte for lithium ion secondary battery. Adding the PEG-borate ester into the electrolyte shows the increase in the ionic conductivity of the polymer electrolyte. By measuring the glass-transition temperature of the polymer electrolytes with DSC, it is found that the increase in ionic conductivity of the polymer electrolyte is due to the increase in ionic mobility. By investigating the temperature dependence of the ionic conductivity of the polymer electrolytes using William-Landel-Ferry type equation, we considered that the PEG-borate ester does not have any influence for dissociation of Li-salt. This revised version was published online in August 2006 with corrections to the Cover Date.     

Anion receptor-coated separator for lithium-ion polymer battery

Anion receptor-coated separators were prepared by coating poly(ethylene glycol) borate ester (PEGB) as an anion receptor and poly(vinyl acetate) (PVAc) as a good adhesive material towards electrodes onto microporous polyethylene (PE) separators. Gel polymer electrolytes were fabricated by soaking them in an liquid electrolyte, 1 M LiPF₆ in EC/DEC/PC (30/65/5, wt.%). As the weight ratio of PEGB to PVAc in a coating layer increased, gel polymer electrolytes showed higher cationic conductivity and electrochemical stability. The cationic conductivity and electrochemical stability of the gel polymer electrolyte based on coated separator with PVAc/PEGB (2/5, weight ratio) could reach 2.8 × 10^–4 S cm^–1 and 4.8 V, respectively. Lithium-ion polymer cells (LiCoO₂/graphite) based on gel polymer electrolytes with and without PEGB were assembled, and their electrochemical performances were evaluated.     

HYDROPHILIC MODIFICATION OF PPESK POROUS MEMBRANES VIA AQUEOUS SURFACE-INITIATED ATOM TRANSFER RADICAL POLYMERIZATION

Hydrophilic surface modification of poly(phthalazinone ether sulfone ketone)(PPESK) porous membranes was achieved via surface-initiated atom transfer radical polymerization(ATRP) in aqueous medium.Prior to ATRP.chloromethyl groups were introduced onto PPESK main chains by chloromethylation.Chloromethvlated PPESK(CMPPESK) was fabricated into porous membrane through phase inversion technique.Hydrophilic poly(poly(ethylene glycol) methyl ether methacrylate)(P(PEGMA)) brushes were grafted from CMPPESK membra...