一种新型凝胶态聚合物电解质的制备和性能

采用一种新型胶联剂新戊二醇二丙烯酸酯(noepentyl glycol diacrylate, NPGDA)和聚偏氟乙烯-六氟丙烯(poly(vinylidene fluoride-co-hexafluoropropylene), PVDF-HFP), 液态电解液组成电解质混合溶液, 然后加入引发剂并加热引发聚合反应制备了一种具有互穿聚合物网络结构的凝胶态聚合物电解质, 可以用于制备聚合物锂离子二次电池. 考察了不同PVDF-HFP/NPGDA质量比对凝胶态聚合物电解质性能的影响. 结果表明, PVDF-HFP/NPGDA质量比可以影响凝胶态聚合物电解质的结构形貌、电化学特性以及聚合物锂离子二次电池的性能. 研究发现, 当m(PVDF-HFP)/m(NPGDA)＝1:1时制备的凝胶态聚合物电解质具有较高的离子电导率和电化学稳定窗口, 室温下分别为6.99×10^-3 S•cm^-1和4.8 V(vs Li⁺/Li), 以其为电解质制备的聚合物锂离子二次电池具有较好的电化学性能.     

辐照交联法制备锂离子电池用凝胶聚合物电解质及其性能

采用γ-射线辐照交联法制备了具有网络结构的聚偏氟乙烯-六氟丙烯/新戊二醇二丙烯酸酯(PVDF-HFP/NPGDA)基凝胶聚合物电解质(GPE). 考察了不同辐照剂量对凝胶电解质形貌结构、热稳定性和电化学性能的影响以及不同辐照剂量和不同温度下电导率的变化. 结果表明, 随辐照剂量的增加, 凝胶电解质的固化程度提高, 电导率下降. 电导率随温度的变化符合VTF方程. 当辐照剂量为5 kGy 时, 制备的凝胶电解质具有较高的离子电导率和电化学稳定窗口, 室温下分别为7.8×10-3 S·cm-1和4.7 V(vs Li/Li+). 以其为电解质制备的LiMn2O4∣GPE∣Li聚合物锂离子电池具有较好的循环性能.     

聚合物电解质界面性质交流阻抗研究

合成了一种新型聚合物基质材料聚(甲基丙烯酸甲酯-丙烯腈-甲基丙烯酸锂)(简记为PMAML),并以PMAML/PVDF-HFP(偏氟乙烯-六氟丙烯共聚合物)复合物为基质制备了聚合物电解质.利用FTIR对合成的PMAML进行结构表征,并用扫描电镜观察聚合物基质膜的表面形貌.聚合物电解质由聚合物基质膜浸渍电解质溶液得到,其室温电导率可达到2.6×10－3 S• cm－1.利用交流阻抗技术研究了聚合物电解质与锂电极间的界面性质,并考察了开路放置时间、循环伏安及恒流充电对界面阻抗的影响.结果表明,聚合物电解质与锂电极界面阻抗随放置时间的延长而增加,更新锂电极表面可降低界面阻抗,PMAML能提高界面稳定性.     

离子液体/凝胶聚合物电解质的制备及其与LiFePO_4的相容性

以1-甲基-3-乙基咪唑六氟磷酸盐(EMIPF6)、聚偏氟乙烯-六氟丙烯(P(VDF-HFP))和六氟磷酸锂(LiPF6)为原料,采用溶液浇铸法制备了离子液体/凝胶聚合物电解质(ILGPE).通过循环伏安(CV)、计时电流法、恒流充放电、电化学阻抗法(EIS)研究了该电解质的离子传输特性以及与锂离子电池正极材料LiFePO4的相容性.结果表明,离子液体/凝胶聚合物电解质的室温电导率为1.650×10-3S·cm-1,电化学稳定窗口达到5.0V.在充放电循环过程中,电极表面形成的钝化膜改善了锂离子脱、嵌可逆性和电极/电解质的界面性质.     

一种新型聚合物电解质的研制

合成了聚 (甲基丙烯酸甲酯 丙烯腈 甲基丙烯酸锂 ) (简记为PMAML)新型聚合物电解质基质材料 ,把它与聚偏氟乙烯 (PVDF)共混制备了凝胶化的聚合物电解质 .通过核磁共振波谱确定了PMAML的组份含量 ,并用扫描电镜观察了该聚合物基质膜的表面形貌 .利用交流阻抗技术测试了其电导率 ,室温下电导率可达2 5× 10 - 3S·cm- 1 .采用线性伏安扫描方法研究了该聚合物电解质的电化学稳定性 ,其电化学稳定窗口为4 5V .通过受限扩散实验测得电解质中离子的扩散系数为 8 12× 10 - 7cm2 ·s- 1 .组装的聚合物电解质锂离子电池首次充放电效率为 89% ,前 5次循环容量基本稳定 .     

P(VDF-HFP)-PMMA/CaCO3(SiO2)复合聚合物电解质的电化学性质

采用激光扫描共焦显微镜、X射线衍射、循环伏安和交流阻抗等方法对由聚(偏二氟乙烯-六氟丙烯)(P(VDF-HFP))、聚甲基丙烯酸甲酯(PMMA)以及纳米碳酸钙(二氧化硅)制备的几种复合聚合物电解质(CPE)膜P(VDF-HFP)-PMMA/CaCO3(SiO2)的性能进行了研究. 结果表明, PMMA的加入能提高CPE的吸液率, 从而增大其离子导电率. 在P(VDF-HFP)与PMMA质量比为1:1条件下制得的CPE性能最佳. 用P(VDF-HFP)-PMMA为聚合物基体与纳米级SiO2、CaCO3进行复合制成的聚合物膜, 无机粒子的加入没有破坏原来聚合物非晶结构; 室温下CPE的电导率达到3.42 mS·cm-1; 电化学稳定窗口为4.8 V. 电池Li/CPE/GMS(石墨基材料)的测试证明, CPE与石墨负极有很好的相容性. 聚合物电池Li/CPE(CaCO3)/LiCoO2比Li/CPE)(SiO2)/LiCoO2具有更优越的倍率放电性能.     

P（VDF-HFP）-PMMA/CaCO3（SiO2）复合聚合物电解质的电化学性质

采用激光扫描共焦显微镜、X射线衍射、循环伏安和交流阻抗等方法对由聚(偏二氟乙烯-六氟丙烯)(P(VDF-HFP))、聚甲基丙烯酸甲酯(PMMA)以及纳米碳酸钙(二氧化硅)制备的几种复合聚合物电解质(CPE)膜P(VDF-HFP)-PMMA/CaCO3(SiO3)的性能进行了研究.结果表明,PMMA的加入能提高CPE的吸液率,从而增大其离子导电率.在P(VDF-HFP)与PMMA质量比为1:条件下制得的CPE性能最佳.用P(VDF-HFP)-PMMA为聚合物基体与纳米级SiO2、CaCO3进行复合制成的聚合物膜,无机粒子的加入没有破坏原来聚合物非晶结构;室温下CPE的电导率达到3.42 mS·cm1;电化学稳定窗口为4.8 V.电池Li/CPE/GMS(石墨基材料)的测试证明,CPE与石墨负极有很好的相容性.聚合物电池Li/CPE(CaCO3)/LiCoO2比Li/CPE)(SiO2)/LiCoO2具有更优越的倍率放电性能.     

聚偏氟乙烯电纺膜及其电化学性能的研究

用电纺的方法制备了聚偏氟乙烯纳米纤维膜,它们具有多微孔结构,能够作为锂电池聚合物电解质.电纺中聚合物溶液的浓度对制备的电纺膜的结构形态有很大的影响,低浓度(10 wt%)时得到珠丝结构的膜,浓度15 wt%时则为纤维结构,而高浓度(18 wt%)时,电纺膜为交联的网状结构.用电纺法制备的聚偏氟乙烯纳米纤维微孔膜具有较高的孔隙率,而且它们与锂金属电极具有良好的界面稳定性;在25℃时吸液率最高可达340%,以这种膜制备的聚合物电解质室温电导率可达到1.57×10-3S.cm-1;由该电解质组装的扣式电池以0.5 mA.cm-2恒流充放电,25℃时50次循环后几乎无容量损失,具有良好的循环性能;即使60℃时,电池仍能保持良好的工作稳定性.     

Al2O3掺杂的复合聚合物电解质室温电导研究

1973年 Wright等[1] 首先报道了 PEO-Li+ 盐的固态聚电解质体系 ,我们从 90年代开始研究物质在聚合物电解质中的传输机理及固 -固界面动力学等问题 [2～ 4 ] .由于聚合物电解质易成膜 ,在制备高能密度全固态电池和光电化学器件等方面具有广泛的应用前景 .目前研究的聚电解质主要为通过加入金属盐而具有导电性的聚合物材料 .PEO具有良好的机械性能和化学稳定性 ,从而成为研究最为广泛的高分子材料 .金属盐溶于 PEO后 ,易形成晶态复合物 ,其电导率仅为 1 0 - 7～ 1 0 - 8S/cm,与应用中所要求的 1 0 - 3 S/cm相差甚远 .因此 ,如何提高 PE…     

一种新型锂离子电池用聚合物电解质复合膜的制备和性能表征

阐述了一种新型锂离子电池用PVDF-HFP(聚偏氟乙烯-六氟丙烯聚合物树脂)基聚合物电解质复合膜的制备过程. 对复合膜中使用的无机TiO2纳米颗粒进行固体超强酸化处理, 并进行颗粒表面酸强度H0测试、XRD晶体结构分析以及复合膜的电解液吸附率测试和电化学阻抗谱测试. 采用PE无纺布支撑体作为增强材料, 以浸涂方法制备复合膜,并进一步组装为锂离子电池, 性能测试表明该电池具有良好的电化学性能.     

Fabrication and characterization of P(VDF-HFP)/SBA-15 composite membranes for Li-ion batteries

This study reports on the preparation of a composite polymer electrolyte for secondary lithium-ion battery. Poly(vinylidiene fluoride-hexafluoropropylene) (P(VDF-HFP)) was used as the polymer host, and mesoporous SBA-15 (silica) ceramic fillers used as the solid plasticizer were added into the polymer matrix. The SBA-15 fillers with mesoporous structure and high specific surface can trap more liquid electrolytes to enhance the ionic conductivity. The ionic conductivity of P(VDF-HFP)/SBA-15 composite polymer electrolytes was in the order of 10⁻³ S cm⁻¹ at room temperature. The characteristic properties of the composite polymer membranes were examined by using FTIR spectroscopies, scanning electron microscopy (SEM), and an AC impedance method. For comparison, the LiFePO₄/Li composite batteries with a conventional microporous polyethylene (PE) separator and pure P(VDF-HFP) polymer membrane were also prepared and studied. As a result, the LiFePO₄/Li composite battery comprised the P(VDF-HFP)/10 wt.% m-SBA-15 composite polymer electrolyte, which achieves an optimal discharge capacity of 88 mAh g⁻¹ at 20 C rate with a high coulomb efficiency of 95%. It is demonstrated that the P(VDF-HFP)/m-SBA-15 composite membrane exhibits as a good candidate for application to LiFePO₄ polymer batteries.     

P(VAc-MA)/PMMA为基体的聚合物电解质制备及其在电致变色器件中的应用

以醋酸乙烯酯(VAc)和丙烯酸甲酯(MA)为单体, 采用半连续种子乳液聚合法制备了无规共聚物P(VAc-MA), 以PMMA与P(VAc-MA)的共混物为基体制备了聚合物电解质. 用红外光谱(FTIR)、X射线衍射(XRD)、热重分析(TG)、紫外光谱(UV)、力学性能测试及电化学交流阻抗等方法研究了聚合物、聚合物膜和聚合物电解质的性质. 结果表明, VAc与MA通过打开各自的CC键聚合生成P(VAc-MA); P(VAc-MA)与PMMA共混后结晶状态发生了变化, 增加了无定形相区, 降低了链段运动的能量壁垒, 提高了热稳定性和拉伸强度. 以P(VAc-MA)/PMMA为基体的聚合物电解质膜具有很高的透明性, 最大室温电导率达到1.17×10-3 S/cm; 离子电导率随着温度的升高而迅速增加, 电导率-温度曲线符合Arrhenius方程; 将此电解质用于全固态电致变色显示器件显示出优良的性能.     

Improving the performance of all-solid-state supercapacitors by modifying ionic liquid gel electrolytes with graphene nanosheets prepared by arc-discharge

Ionic liquid gel polymers have widely been used as the electrolytes in all-solid-state supercapacitors, but they suffer from low ionic conductivity and poor electrochemical performance. Arc discharge is a fast, low-cost and scalable method to prepare multi-layered graphene nanosheets, and as-made graphene nanosheets （denoted as ad-GNSs） with few defects, high electrical conductivity and high thermal stability should be favorable conductive additive materials. Here, a novel ionic liquid gel polymer electrolyte based on an ionic liquid （EM1MNTF2） and an copolymer （P（VDF-HFP）） was modified by the addition of ad-GNSs as an ionic conducting promoter. This modified gel electrolyte shows excellent thermal stability up to 400 ℃ and a wide electrochemical window of 3 V. An all-solid-state supercapacitor based on commercial activated carbon was fabricated using this modified ionic liquid gel polymer electrolyte, which shows obviously improved electrochemical behaviors compared with those of the corresponding all-solid-state supercapacitor using pure ionic liquid gel polymer electrolyte. Specially, smaller internal resistance, higher specific capacitance, better rate performance and cycling stability are achieved. These results indicate that the ionic liquid gel polymers modified by ad-GNSs would be promising and suitable gel electrolytes for high performance all-solid-state electrochemical devices.     

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。     

纳米Al2O3填充的PVDF-HFP复合电解质的导电性

用真空蒸发法制备了不同配方的PVDF-HFP复合电解质膜,通过交流阻抗测试,优选出机械和电化学性能较好的PVDF-HFP复合电解质的工艺参数,m(纳米Al₂O₃)∶m(增塑剂DBP)∶m(PVDF-HFP)=10∶45∶45.用丙酮抽提制得的PVDF-HFP聚合物膜中的增塑剂,再于1mol/LLiPF₆/DEC-EC(体积比1∶1)的液态电解质中浸渍,浸渍后聚合物膜的电导率达到10-3S/cm数量级.     

1H-1,2,4-Triazole as solvent for imidazolium methanesulfonate

The solvation effect of 1H-1,2,4-triazole towards imidazolium methanesulfonate was studied by blending imidazolium methanesulfonate and 1H-1,2,4-triazole. Upon addition of 1H-1,2,4-triazole, the melting point of imidazolium methanesulfonate was lowered to less than 100 °C while maintaining the high ionic conductivity for a wide composition range of the blend. The ionic conductivity of the blend can be adequately described by using the Vogel-Fulcher-Tamman equation. A vehicle mechanism is postulated to govern the proton conduction for the blend. The contribution of protons to the ionic conductivity was corroborated electrochemically. The blend exhibited electrochemical activities for H(2) oxidation and O(2) reduction at a Pt electrode, as well as a wide electrochemical window. Therefore, suitable blends can possibly serve as electrolytes for polymer electrolyte membrane fuel cells operating under non-humidifying conditions. The solvation effect studied herein suggests a promising approach to a wider application area of protic ionic liquids.     

Ionic transport in P(VDF-HFP)-PMMA-LiCF3SO3-(PC + DEC)-SiO2 composite gel polymer electrolyte

Composite gel polymer electrolytes composed of poly(vinylidene fluoride-co-hexafluoropropylene) P(VDF-HFP) and polymethylmethacrylate PMMA polymers, PC + DEC as plasticizer and LiCF₃SO₃ as salt and fumed silica as filler have been synthesized by solvent casting technique with varying plasticizer-filler ratio systematically. Films of thickness in the range of 40-70 μm were characterized by a.c. impedance measurements in the temperature range 303 K to 373 K. Addition of filler to the polymer electrolyte was found to result in an enhancement of the ionic conductivity. A maximum electrical conductivity of ∼1 × 10⁻³ S/cm at 303 K and ∼2.1 × 10⁻³ S/cm at 373 K has been achieved with the dispersion of the SiO₂. FTIR spectral studies confirmed the polymer-salt interaction. XRD patterns exhibit the increased amorphicity in the blended composite gel polymer electrolytes. Scanning electron micrograph shows the dispersion of SiO₂ particle in the polymer electrolyte.