增塑聚合物电解质电化学性能

以GBL/EC复配体系为增塑剂, PVDF HFP和PMMA为聚合物基体制备胶态聚合物电解质. 研究聚合物电解质的离子传输特性和电化学稳定性. 实验表明,室温离子电导率达到 1. 2mS·cm-1, 电化学稳定窗口在 4. 5V以上. 以GBL/EC增塑聚合物电解质与表面经修饰的锂金属电极组成锂金属聚合物电池,其电极稳定性较好,充放电循环寿命得到很大的提高.     

静电纺丝交联凝胶聚合物电解质的制备与表征

利用静电纺丝技术和傅-克烷基化反应制备了以聚偏氟乙烯(PVDF)为基体,聚苯乙烯-聚环氧乙烷-聚苯乙烯(PS-PEO-PS)三嵌段共聚物为添加剂的交联纳米纤维复合膜(e-CPMs).将e-CPMs浸泡电解液活化,即可得到交联凝胶聚合物电解质(e-CGPEs).通过改变PS-PEO-PS的含量(3%、5%、10%、20%)研究了PS-PEO-PS对e-CPMs热稳定性及e-CGPE电化学性能的影响.结果表明,e-CPMs的高温尺寸稳定性优于PVDF膜和商业化聚丙烯(PP)隔膜.当PS-PEO-PS的添加量达到5%时,e-CGPE 5%的室温离子电导率可达6.52 mS/cm.在2 C充放电,e-CGPE 5%放电比容量仍可达83.5 mAh/g.在0.1 C循环100次后,e-CGPE 5%的放电容量保持率高达99.7%.     

“Water-in-salt”聚合物电解质制备及其电化学性能研究

为提高柔性锂离子电池安全性和循环稳定性能,本实验以自由基聚合结合冷冻干燥得到的聚丙烯酰胺膜为电解质载体,引入21 mol·kg^-1 LiTFSI 高浓度电解液,得到“water-in-salt”聚合物电解质。通过聚合物膜的形貌和孔道结构表征,红外光谱分析,离子电导率及电化学稳定窗口测试等对其基本物化特性进行了研究。冷冻干燥得到的聚丙烯酰胺膜内部具有大量微孔结构,有利于电解液的载入。将该吸附了电解液的聚合物电解质膜与锰酸锂(LiMn₂O₄)正极和磷酸钛锂(LiTi₂(PO₄)₃)负极组装全电池进行充放电性能测试。结果表明,制得的柔性聚合物电解质具有良好的拉伸性能,高离子电导率(20°C,4.34 mS·cm^-1)和宽电化学稳定窗口(3.12 V)。以“water-in-salt”聚合物电解质为隔膜组装的LiMn₂O₄||LiTi₂(PO₄)₃ 全电池表现出优异的倍率性能和长循环稳定性。     

高性能锂离子电池隔膜的结构设计及其制备与表征

设计并采用高压静电纺丝法制备了单层结构的聚偏氟乙烯(PVDF)/偏氟乙烯与六氟丙烯的共聚物(PVDF-HFP)纳米纤维膜及三层结构、二层结构的PVDF/PVDF-HFP/Al2O3复合纳米纤维膜.复合膜的表面形貌、热物理性质和电化学性能通过扫描电子显微镜(SEM)、示差扫描量热法(DSC)、高温尺寸收缩率、交流阻抗法进行了表征.单层结构的PVDF/PVDF-HFP纳米纤维膜的纤维表面光滑,平均纤维直径2μm,纤维分布较均匀,而PVDF与Al2O3复合后的纤维表面粗糙,平均纤维直径变小,结晶度降低,吸液率增大.二层结构的PVDF/PVDF-HFP/Al2O3复合隔膜在170℃下受热1 h收缩率为3%.将3种结构的复合膜在1 mol/L Li PF6/(EC+DMC+DEC,1∶1∶1,W/W/W)电解质溶液中活化得到聚合物电解质.25℃时,二层结构的PVDF/PVDF-HFP/Al2O3复合隔膜吸液率高达497 wt%,离子电导率可达5.04×10-3S/cm,电化学稳定窗口达到4.62 V(Li/Li+).组装成Li Fe PO4/Li电池测试其电池性能,结果表明,二层结构的PVDF/PVDF-HFP/Al2O3复合膜朝向锂负极时,电池的循环性能更好,且与锂金属负极具有更好的相容性和界面稳定性.     

聚乙烯吡咯烷酮基碘凝胶电解质的制备及在染料敏化太阳能电池中的应用

采用聚乙烯吡咯烷酮(PVP)和聚偏氟乙烯(PVDF)为凝胶剂, 以碘化锂和碘单质为碘源, 碳酸乙烯酯(EC)和碳酸丙烯酯(PC)为溶剂, 制备了染料敏化太阳能电池(DSSCs)用凝胶聚合物电解质(GPE). 使用拉曼光谱、 循环伏安曲线和交流阻抗谱等对GPE进行表征. 结果表明, 聚合物的配比与浓度及碘与碘化锂比例对该电解质性能有很大影响, 当聚合物质量分数为10%、 PVP与PVDF质量比为80∶20、 I₂浓度为0.042 mol/L且LiI与I₂摩尔比为30∶1时, 制备的GPE在室温下电导率达最大值(3.27 mS/cm). 使用该GPE组装的DSSCs在100 mW/cm²的模拟太阳光照射下, 开路电压为0.64 V, 短路电流为13.6 mA/cm², 填充因子为0.595, 能量转化效率为5.18%, 并在30 d内表现出了良好的稳定工作性能.     

新型PMMA基聚合物电解质的研制

制备了聚甲基丙烯酸甲酯（PMMA）基聚合物电解质，通过加入交联剂使其形成网状结构，提高了聚合物电解质的机械性能.对MMA以及交联剂的含量作了优化，并测试了聚合物电解质的温度特性.测试结果表明,MMA、EGD(二甲基丙烯酸乙二醇酯)和电解液(LiBF4/EC DMC)含量分别为25％、2％、73％(质量分数）时，所制备的聚合物电解质具有较高的电导率，室温条件下可以达到2×10－3 S•cm－1，电化学窗口为4.8 V.用其作为电解质组装的聚合物锂离子电池具有较好的充放电性能.     

基于静电纺丝和静电喷射技术的P(VDF-HFP)/Al_2O_3/P(VDF-HFP)复合隔膜的制备与电化学性能分析（英文）

通过静电纺丝和静电喷射技术,将三氧化二铝(Al_2O_3)纳米颗粒沉积在两层聚四氟乙烯六氟丙烯[P(VDF-HFP)]静电纺丝隔膜之间,制备出了具有"三明治"结构的P(VDF-HFP)/Al_2O_3/P(VDF-HFP)复合锂离子电池隔膜.分析了隔膜的形态结构、热收缩性能、拉伸性能、电化学性能以及隔膜在电池中的循环性能.测试结果表明,该复合隔膜比纯P(Vd F-HFP)膜拥有更高的吸液率,隔膜更容易吸收电解液从而形成凝胶聚合物电解质(GPEs).该复合隔膜的拉伸强度在4 MPa左右,相对应的断裂伸长率为261.57%.复合隔膜在室温下的离子电导率为1.61×10~(-3)S/cm,且表现出了较高的电化学稳定性(电化学稳定窗口达到5.4 V).在电池的循环测试中,使用钴酸锂(LiCoCO_2)作为正极材料,由该复合隔膜组装的电池的首次放电比容量达到了理想的水平,为145 m A·h·g~(-1).     

基于静电纺丝和静电喷射技术的P(VDF-HFP)/Al2O3/P(VDF-HFP)复合隔膜的制备与电化学性能分析

通过静电纺丝和静电喷射技术, 将三氧化二铝(Al₂O₃)纳米颗粒沉积在两层聚四氟乙烯六氟丙烯[P(VDF-HFP)]静电纺丝隔膜之间, 制备出了具有“三明治”结构的P(VDF-HFP)/Al₂O₃/P(VDF-HFP)复合锂离子电池隔膜. 分析了隔膜的形态结构、 热收缩性能、 拉伸性能、 电化学性能以及隔膜在电池中的循环性能. 测试结果表明, 该复合隔膜比纯P(VdF-HFP)膜拥有更高的吸液率, 隔膜更容易吸收电解液从而形成凝胶聚合物电解质(GPEs). 该复合隔膜的拉伸强度在4 MPa左右, 相对应的断裂伸长率为261.57%. 复合隔膜在室温下的离子电导率为1.61×10^-3 S/cm, 且表现出了较高的电化学稳定性(电化学稳定窗口达到5.4 V). 在电池的循环测试中, 使用钴酸锂(LiCoCO₂)作为正极材料, 由该复合隔膜组装的电池的首次放电比容量达到了理想的水平, 为145 mA·h·g^-1.     

MCM-48改性PVDF-HFP复合多孔型聚合物电解质

采用倒相法,以MCM-48介孔分子筛作填料,由偏氟乙烯-六氟丙烯的共聚物(PVDF-HFP)制备一种复合多孔型聚合物电解质.其离子电导率比未改性的PVDF-HEP提高了约97%(从0.89mS/cm提高到1.75mS/cm),离子迁移数提高约39%(从0.57提高到0.79),且聚合物的结晶度和电化学稳定性没有明显改变.由该复合聚合物电解质组装的扣式电池首次充放电效率为91%,经过30次循环后,容量几乎没有衰减;1C放电容量为0.1C放电容量的80%.     

聚乙烯醇基水凝胶聚合物电解质超级电容器的研究

以2-丙烯酰胺基-2-甲基丙磺酸（AMPS）作引发剂引发交联聚乙烯醇（PVA）-戊二醛（GA）制备水凝胶聚合物电解质并组装成超级电容器.分别由红外光谱、交流阻抗、循环伏安与恒电流充放电曲线测定该凝胶聚合物电解质及超级电容器的电化学性能.结果表明,该聚合物电解质电导率可达1.23 mS/cm（室温）.而且,以1.0 g AMPS引发0.05mL GA（5 %）与1.0 g PVA交联,制得的凝胶聚合物电解质超级电容器比电容可达139F/g,50次充放电后其值仍于80%以上.     

SPECTRAL CHARACTERISTICS OF THE EXCITED STATES OF THE PRODUCT OF THE CHEMILUMINESCENCE OF LUMINOL*

Abstract— In dimethylsulfoxide the emission spectrum of luminol chemiluminescence is red-shifted by 300 cm^-1 from the photoexcited fluorescence of the product 3-aminophthalate dianion, while in aqueous solvent the two spectra are identical. The spectral properties of the product dianion have been measured in aqueous solvent and in a number of aprotic solvents, both at room temperature and at 77°K. The ground states and the excited states from which emissions are observed are characterized. Two alternatives are presented to explain the aprotic emission spectra.     

ON THE ACCURACY OF DIFFERENTIAL MEASUREMENTS OF THE MINIMAL ERYTHEMA DOSE: INFLUENCE OF THE DISCRETENESS OF THE SCALE

The minimal erythema dose (MED) is often used as a quantity by which the influence of certain treatments of the skin can be measured. Differential measurements are performed by assessing the difference of the MED on the skin treated in some way and the untreated skin.
As the MED-measuring scale is discrete, the question is sometimes raised whether it is possible to measure differences smaller than one scale unit. In the present paper it is shown that this is indeed possible; in principle the discreteness of the scale does not impose any restriction on the smallest value of the difference that can be measured. The discreteness of the scale introduces an extra random variation into the measurement. This variation is estimated theoretically. It is automatically included in the usual error analysis.
The discreteness variance is small when compared to other variance components, which are computed from an analysis of variance of actual experiments. Reducing the discreteness variance, by reducing the dose decrement of the MED-measuring scale, therefore, does not enhance the overall accuracy considerably. Finally, it is found that the assessments of the MED by the various observers do not differ significantly from each other, and that multiple assessments do increase the accuracy, especially for small effects.     

光谱透射比标准物质的研究

研制了紫外、可见、近红外光谱区通用光谱透射比较标准物质。以高纯熔融石英为基片材料，镍铬合金的镀膜材料，采用双光楔对称光胶结构以消除同色杂散光的影响，对镀膜进行光胶处理以保证膜层的强度、稳定性及光学中性，采用高精度分光光度测量装置作为定值手段的以保证准确的定值，设计定位保护架以消除多次反射误差。该光度标准适用的光谱范围的200-2600nm，光谱透射比定值不确定度为0.5%。     

丙烯聚合络合催化剂形成过程的研究

以倍半物为还原剂还原TiCl_4,经异戊醚络合处理,然后在TiCl_4己烷溶液中35℃条件下热处理,制得对丙烯聚合具有高活性和高定向度的络合催化剂。研究了制备过程中各步反应产物的组成和结构特征,并讨论了TiCl_3低温晶型转变机理。     

分光光度法低浓度区不成线性关系的探讨

本文研究分光光度法低浓度区不成线性的有关因素及其克服方法,以铝-二甲酚橙体系为例,通过对体系不同条件下吸收光谱及其等色点的研究,发现当体系pH渐变时(铝,二甲酚橙浓度固定不变),曲线簇现两个等色点.从对等色点的分析,证明体系形成络合物须按一个反应式进行才能出现等色点,而与反应式是否涉及到两个或三个有色化合物无关.若同时按两个反应式进行,则不能得到等色点,测定时也无线性关系.所以用这个体系进行铝的测定,铝浓度的变化范围只能限于存在等色点的区间才有线性关系. 为了克服常法测定铝时不符线性的现象,本文采用的方法是在二甲酚橙中预先加适量的铝作为显色剂,使反应严格按一个反应式进行,所得结果为一直线.     

对苯二胺衍生物的光催化氧化

以ＴｉＯ２作为催化剂，利用波长＞３３０ｎｍ的光辐照研究了Ｎ－取代的对苯－二胺衍生物的光催化氧化。研究表明，氧分子与光生电子 反应生成羟基自由基，羟基自由基氧化ＰＰＤｓ，生成醌二亚胺，后者在羟基的进攻下脱氨生成苯醌，苯醌继续光解无机化。ＰＰＤｓ光催化氧化近似遵循一级反应动力学，醇类和硫酸根离子可抑制ＰＰＤｓ的光催化氧化。催化剂表面荷影响电子转移速率，从而控制光催化氧化的反应速率。     

THE COMPLEXITY OF THE FLUORESCENCE OF CHLORELLA PYRENOIDOSA

Abstract— The complexity of the room-temperature emission spectrum of Chlorella was investigated by a matrix analysis method. This approach revealed the presence of two independently fluorescent components in the short-wave region of the spectrum. These components, maximal at about 687 and 695 nm, appeared to correspond to the fluorescence of the bulk pigments of PS II and PS I respectively. The analysis was insensitive to the individual species within the photosystems. As such, other minor fluorescent species, usually observed at low temperatures, which presumably correspond to fluorescence from the trapping centres, did not appreciably complicate the analysis. The absorption spectra of the two photosystems were calculated from the fluorescence data. The results were similar to those that have been obtained by other workers from oxygen evolution and DCMU poisoning data but differed from those obtained by computer analysis of the absorption spectrum. Addition of reduced DCPIP was observed to reverse the increase in fluorescence yield and changes in the spectral distribution of emission taking place on poisoning the algae. The correlation between this and the catalysis of photophos-phorylation in aged or poisoned chloroplasts was noted. This correlation was tentatively interpreted as evidence for a direct interaction between the donor system and the photochemical apparatus associated with PS II, rather than with a member of the electron transport chain as is normally assumed.     

六氟丙烯等离子体聚合机理研究

<正> 在以前的工作中,我们曾应用色谱-质谱(GC-MS)及顺磁共振(ESR)等方法研究了四氟乙烯和三氟氯乙烯等离子体聚合过程中气体冷凝物的组成及结构,提出自由基引发聚合反应机理。本文用类似方法研究六氟丙烯(HFP)等离子体气体冷凝物的组成与结构和冷凝物的ESR信号及其从低温到高温的变化规律,证实了自由基的稳定性并提出气相聚合反应机理。     

THE KINETICS OF THE DECOMPOSITION OF CYCLOHEXYL HYDROPEROXIDE IN THE PRESENCE OF VANADYL DIBENZOYLMETHANE

The kinetics of the decomposition of cyclohexyl hydroperoxide(CHHP) in benzene catalyzed by vanadyl dibenzoylmethane[V0(DBM).,] has been studied.It was found that the products of decomposition of CHHP were cyclohexanol and cyclohexanone,which are produced in about equimolar amount,and the product cyclohexanol obviously inhibited the decomposition of CHHP.The kinetics data can be satisfactorily described by the following equation (with [CHHP]0>>[VO(DBM)2]0)R0=kK[CHHP]0[VO(DBM)2]0/(1+k[CHHP]0)This is the kinetic evidence for the formation of a catalyst-hydro-peroxide intermediate.In the equation K is the stability constant of the catalyst-hydroperoxide intermediate complex;k is the rate constant for the decomposition of the complex.The rate constant K at 500℃ may be expressed as follows:k=1.9×108exp(-53.7×103/RT)S-1 with the activation energy Ea=53.7kJ mol-1