修饰LB膜法制备聚3,4-乙烯二氧噻吩薄膜

采用修饰Langmuir-Blodget(LB)膜法以二十烷酸(AA) LB膜为模板, 通过3,4-乙烯二氧噻吩(EDOT)单体在LB膜亲水基团间聚合, 制备了AA/PEDOT复合LB膜. 实验分析表明薄膜具有较好的层状有序结构, 并进一步研究发现EDOT在AA多层膜中的聚合破坏了原有LB膜的有序性, 这与聚合过程对层状结构产生的破坏作用有关; 研究了薄膜导电性能, 发现AA/PEDOT多层膜的电导率随处理时间的变化产生突变, 这与多层膜中导电通道的“渝渗”有关, 在有效导电网络连通后电导率发生了突变. 测试结果还表明AA/PEDOT膜导电性明显优于PEDOT旋涂膜和十八胺-硬脂酸/聚(3,4)乙烯二氧噻吩-聚苯乙烯磺(ODA-SA/PEDOT-PSS)复合膜.     

石墨烯/聚3，4-乙烯二氧噻吩复合物的电化学制备及其在超级电容器中的应用

首次提出了一种在离子液体中在石墨烯表面用恒电流法聚合3,4-乙烯二氧噻吩(EDOT)单体制备石墨烯/聚3,4-乙烯二氧噻吩(石墨烯/PEDOT)复合物的方法。用原子力显微镜、扫描电镜等技术表征证明石墨烯/PEDOT复合物是由PEDOT纳米谷粒状颗粒分散在石墨烯片表面而组成的。将该复合物用作超级电容器电极材料时,在1.0 A.g-1的充放电比电流下得到的比电容值为181 F.g-1。同时,该材料还显现出较好的充放电可逆性和稳定性。     

基于3,4-乙烯二氧噻吩和吡咯-3-甲酸的共聚物薄膜的制备、表征及电致变色性能

以3,4-乙烯二氧噻吩(EDOT)和吡咯-3-甲酸(P3C)为共聚单体,EDOT和P3C分别按物质的量比1∶1,3∶1,5∶1,10∶1配比,通过电化学聚合制得了4种聚(3,4-乙烯二氧噻吩-吡咯-3-甲酸)薄膜,并依次命名为P(EDOT∶P3C)-1,P(EDOT∶P3C)-3,P(EDOT∶P3C)-5和P(EDOT∶P3C)-10.光谱电化学测试结果表明,4种共聚物薄膜都具有优良的电致变色性能,同时具有较好的电化学活性和较高的光学对比度.与聚3,4-乙烯二氧噻吩(PEDOT)相比,P(EDOT∶P3C)能展示更丰富的颜色变化,如P(EDOT∶P3C)-1薄膜随着电压的变化,可呈现从暗红色、浅褐色、灰蓝色到蓝色的变化.此外,基于EDOT和P3C以及钛氧簇[Ti_7(OEt)_(19)O_5(CoBr)],我们还设计合成了含钛共聚物薄膜P(EDOT∶P3C)-1-Ti,该薄膜不仅具有电致变色性能,而且还具有电催化氧化水的活性.     

聚(3,4-乙撑二氧噻吩)/木质素磺酸导电复合物的结构与性能

3,4-乙撑二氧噻吩(EDOT)以木质素磺酸(LS)作载体,通过化学氧化法聚合形成了聚(3,4-乙撑二氧噻吩)/木质素磺酸(PEDOT/LS)导电复合物.该导电复合物的结构与性能分别采用紫外可见分光光度计、红外光谱仪、zeta电位及粒度分析仪、原子力显微镜、X-射线光电子能谱仪、X-射线衍射仪、四探针测试仪、电泳仪,以及表面电阻仪来表征.结果表明,EDOT能在LS水溶液中氧化聚合,得到水分散性PEDOT/LS导电颗粒.该颗粒是一种聚电解质复合物,等量电荷配比的PEDOT/LS位于内核而富余的亲水性LS包在外层.LS与PEDOT两者之间存在较强的作用力,无法通过电泳分开.X-射线衍射仪结果表明该复合物是无定型的.当LS与EDOT单体质量比从0.7∶1升高至3.0∶1时,复合物的粒径从673 nm降低至348 nm,涂膜表面变得均匀,同时表面电阻从1.9 kΩ/sq上升至87.2 kΩ/sq.用PEDOT/LS配置得到的抗静电剂,可以使玻璃片表面电阻从1012Ω/sq减小至107Ω/sq.     

修饰Langmuir-Blodget膜法制备聚(3,4-亚乙基二氧噻吩)薄膜结构和导电性能的研究

采用修饰Langmuir-Blodget(LB)膜法以二十烷酸(AA)LB膜为模板,通过3,4-亚乙基二氧噻吩(EDOT)单体在LB膜亲水基团间聚合,制备了二十烷酸/聚(3,4-亚乙基二氧噻吩)(AA/PEDOT)复合LB膜.UV-Vis、FTIR和XPS分析表明EDOT在多层膜中有效聚合,生成了PEDOT导电聚合物;X射线衍射(XRD)和二次离子质谱(SIMS)分析表明薄膜具有较好的层状有序结构,进一步研究发现EDOT在AA多层膜中的聚合破坏了原有LB膜的有序性,这可能与聚合过程对层状结构产生的破坏作用有关;采用四探针仪及半导体测试仪研究了薄膜导电性能,发现AA/PEDOT多层膜的电导率随处理时间的变化产生突变,这与多层膜中导电通道的"逾渗"有关,在有效导电网络连通后电导率发生了突变.测试结果还表明AA层和PEDOT层之间具有较为明显的界面,PEDOT显示出较好的定域性,薄膜具有很好的层状有序结构.     

微米级PS-PEDOT核壳型导电微球的合成与拉曼表征

以分散聚合法制备的微米级聚苯乙烯(PS)微球为模板、3,4-乙烯二氧噻吩(EDOT)为单体、过硫酸铵(APS)为引发剂,通过氧化聚合制备了PS-PEDOT核壳型复合导电微球。采用扫描电镜、透射电镜等对导电微球的形貌和结构进行了表征,重点采用拉曼光谱研究了其核壳结构特征。并研究了超声分散、溶液pH以及单体配比对导电微球形貌的影响。实验结果表明:超声的引入可提高导电微球的单分散性,改善微球的形貌。随着pH的降低或单体配比的增加,导电聚合物在PS微球表面的负载量随之增加,当m(EDOT)/m(PS)由0.60增加到1.25时,导电微球的平均粒径由1.76μm增加到1.91μm。     

聚3,4-乙烯二氧噻吩/石墨烯/钛电极的制备及其电化学性能

采用直流电弧等离子体喷射化学气相沉积法把石墨烯生长在钛(Ti)基底上,并采用电化学氧化聚合法在石墨烯表面沉积聚3,4-乙烯二氧噻吩(PEDOT),由此构造PEDOT/石墨烯/Ti电极。形貌及结构表征结果表明,电聚合200圈以上的PEDOT呈线状或泡沫状且均匀分布于石墨烯表面。电化学性能测试结果表明,PEDOT/石墨烯/Ti电极具有高的比电容和库伦效率;其电聚合次数为400圈时,与PEDOT/Ti电极相比,比电容提高42倍,其最大电势窗口可达1.4 V,而在0～1.2 V电势窗口范围内,扫描速度为10 mV·s-1时,比电容可达到269.6 mF·cm-2。     

暗场显微镜下原位监测GNR/PEDOT在ITO界面上组装成膜过程

研究采用电化学聚合法,在中性水溶液中以3,4-乙烯二氧噻吩(EDOT)为反应液,在金纳米棒(GNR)修饰的ITO上聚合成PEDOT导电薄膜,并对该体系的稳定性进行了研究。利用暗场光学显微镜原位实时观察了聚合过程中纳米粒子掺杂的导电聚合物的微结构形貌不断进化,同时原位研究了该体系的光电性质。随着反应时间的增加,掺杂了纳米粒子的PEDOT薄膜的微结构形貌不断进化,从分散的颗粒状态向连续的树枝状态转变,最后成有些微高低起伏的薄膜状。     

导电聚合物超薄膜的制备及性能表征

采用修饰LB膜法制备了导电聚合物聚-3,4-乙烯二氧噻吩/硬脂酸(PEDOT/SA)复合超薄膜. 将硬脂酸(SA)/FeCl3 LB膜暴露于EDOT单体气氛中, EDOT 单体在多层膜中聚合, 制备了PEDOT/SA多层复合LB膜. 紫外-可见光-近红外(UV-Vis-NIR)吸收光谱和X射线光电子能谱(XPS)分析表明EDOT单体在多层膜中发生聚合并生成PEDOT导电聚合物. 扫描电子显微镜(SEM)分析显示生成的PEDOT导电聚合物颗粒分散于硬脂酸LB膜中, 被LB 膜所包裹. 二次离子质谱(SIMS)及XPS分析还发现S元素含量随LB 膜的深度变化而变化, 表明PEDOT 较好地分散于多层膜中. 采用四探针电导率仪对复合多层膜的电导率进行了测试, 结果显示60 层复合LB 膜的电导率为2.6 S·cm-1, 比普通PEDOT薄膜的电导率高一个数量级, 且表现出较好的掺杂/脱掺杂能力. 研究还发现复合膜电导率与薄膜在EDOT 单体中处理时间有关, 处理时间至120 min 后电导率达到最大值并趋于稳定, 氧化剂浓度较低可能影响EDOT在LB膜中的聚合反应速率. 对复合LB 膜的气敏特性进行了分析, 发现在较低气体浓度范围(φ<30×10^-6), PEDOT 复合LB 膜有较快的反应速率, 气敏性与气体浓度呈非线性. 在较高浓度范围(φ=(30-120)×10^-6), 气敏性与浓度呈较好的线性关系. PEDOT复合LB膜对HCl气体表现出较好的响应恢复特性. 同时对PEDOT 复合膜相关的导电机理及气体敏感机理进行了分析.     

导电聚合物有序超薄膜的合成及其作为有机电致发光器件空穴注入层

采用修饰多层LB膜的方法制备了导电聚合物聚-3,4-乙烯二氧噻吩/二十烷酸(PEDOT:AA)复合层状有序膜, 构筑了一种导电聚合物镶嵌的多层有序膜结构. 将这种导电聚合物有序薄膜沉积于ITO电极表面, 将其作为有机电致发光二极管(OLED)的空穴注入层, 并研究了ITO/(PEDOT:AA)/MEH-PPV/Al器件的性能. 研究结果表明, 与采用聚3,4-乙烯二氧噻吩/聚苯乙烯磺酸(PEDOT:PSS)自组装膜和旋涂膜作为空穴注入层的ITO/(PEDOT:PSS)/MEH-PPV/Al器件相比, 器件的发光效率增加, 起亮电压降低. 我们认为这是由于PEDOT:AA薄膜提供了一种有序层状结构后, 减小了ITO与MEH-PPV间的接触势垒, 改善了空穴载流子注入效率. 进一步的研究表明, 由于PEDOT:AA多层膜间靠较弱的亲水、疏水作用结合, 这种导电多层有序膜的热稳定性与普通LB膜相似, 在较高温度下发生从层状有序态到无序态的变化, 这是导致OLED器件性能发生劣化的主要原因.     

四丁基六氟磷酸铵作为锂离子电池阻燃添加剂的研究

近年来关于锂离子电池造成的安全问题甚至事故的报道屡见不鲜,锂离子电池的安全问题已经成为人们关注的焦点. 我们用四丁基六氟磷酸铵（TBAPF₆）作为锂离子电池电解液阻燃添加剂,研究发现添加了TBAPF₆的电解液具有明显的阻燃效果,同时电解液电导率下降并不明显. LiCoO₂/Graphite全电池在添加了TBAPF₆的电解液中可逆容量会略有降低,但具有更优异的循环稳定性. 主要是由于TBAPF₆添加量的增加会影响石墨电极的库伦效率,延长活化时间. 通过对LiCoO₂/Graphite全电池绝热加速量热仪（ARC）测试,表明添加TBAPF₆对电池的燃烧有明显的抑制作用. 在TBAPF₆添加量至5%时,电池在300 ^oC内自放热速率不超过0.1^oC/min,电池的安全性显著提高.     

Fabrication of solid thin film electrolyte and LiCoO2 by aerosol flame pyrolysis deposition

Aerosol flame pyrolysis deposition method was applied to deposit the oxide glass electrolyte film and LiCoO₂ cathode for thin film type Li-ion secondary battery. The thicknesses of as-deposited porous LiCoO₂ and Li₂O–B₂O₃–P₂O₅ electrolyte film were about 6 μm and 15 μm, respectively. The deposited LiCoO₂ was sintered for 2 min at 700 °C to make partially densified cathode layer, and the deposited Li₂O–P₂O₅–B₂O₃ glass film completely densified by the sintering at 700 °C for 1 h. After solid state sintering process the thicknesses were reduced to approximately 4 μm and 6 μm, respectively. The cathode and electrolyte layers were deposited by continuous deposition process and integrated into a layer by co-sintering. It was demonstrated that Aerosol flame deposition is one of the good candidates for the fabrication of thin film battery.     

Three new bifunctional additive for safer nickel-cobalt-aluminum based lithium ion batteries

The phosphorus-containing additives can help for forming a stable solid electrolyte interface film on the NCA cathode, thus enhance the thermal stability of the electrolyte and cycle performance of the battery.     

固态锂电池中正极/电解质界面的密度泛函计算研究

锂离子电池的广泛应用对储能器件的能量密度、安全性和充放电速度提出了新的要求. 全固态锂电池与传统锂离子电池相比具有更少的副反应和更高的安全性,已成为下一代储能器件的首选. 构建匹配的电极/电解质界面是在全固态锂电池中获得优异综合性能的关键. 本文采用第一性原理计算研究了固态电池中电解质表面及正极/电解质界面的局域结构和锂离子输运性质. 选取β-Li₃PS₄ (010)/LiCoO₂ (104)和 Li₄GeS₄ (010)/LiCoO₂ (104)体系计算了界面处的成键情况及锂离子的迁移势垒. 部分脱锂态的正极/电解质界面上由于Co-S成键的加强削弱了P/Ge-S键的强度,降低了对Li⁺的束缚,从而导致了更低的锂离子迁移势垒. 理解界面局域结构及其对Li+输运性质的影响将有助于我们在固态电池中构建性能优异的电极/电解质界面.     

Rational design on separators and liquid electrolytes for safer lithium-ion batteries

As the energy density of lithium-ion batteries (LIBs) continues to increase,their safety has become a great concern for further practical large-scale applications.One of the ultimate solution of the safety issue is to develop intrinsically safe battery components,where the battery separators and liquid electrolytes are critical for the battery thermal runaway process.In this review,we summarize recent progress in the rational materials design on battery separators and liquid electrolyte towards the goal of improving the safety of LIBs.Also,some strategies for further improving safety of LIBs are also briefly outlooked.     

Modification of electrolyte transport within the cathode for high-rate cycle performance of Li-ion battery

During high-rate cycling of Li-ion batteries (LIBs) at elevated temperatures, the detachment of the cathode materials from their Al substrate is a major cause of the deterioration in the performance of LIBs. This detachment is suppressed by the addition of an electrolyte additive, poly(ethylene glycol) methyl ether methacrylate, which can act as a buffer zone to prevent the abrupt mass transport of electrolyte within the cathode and as a swing to transport Li⁺ ions dissociating from the active materials of the cathode. Owing to the dual effects of this type of monomer, an acrylate monomer with one side ether chain, the cathode materials are maintained without detachment from the Al substrate, even under severe cycling conditions. This idea can be applied to LIBs for a series of electric vehicles, which require superior high-rate performance at elevated temperatures.     

基于聚碳酸丙烯酯基聚合物电解质和有机正极的全固态钠电池

Sodium-ion batteries (SIBs) are promising candidates to replace lithium-ion batteries (LIBs) to meet the emergent requirements of various commercial applications. SIBs and LIBs are similar in many aspects, including their reduction potentials, approximate energy densities, and ionic semidiameters. Analogously, safety issues, including liquid leakage, high flammability, and explosiveness limit the usage of SIBs. All-solid-state batteries have the potential to solve the aforementioned problems. However, polycarbonates as promising solid electrolytes have been rarely exploited in all-solid-state SIBs. In addition, organic electrode materials, including non-conjugated redox polymers, carbonyl compounds, organosulfur compounds, and layered compounds, have been intensively investigated as part of various energy storage systems owing to their low cost, environmental friendliness, high energy density, and structural diversity. Nevertheless, the dissolution of small organic compounds in organic-liquid electrolytes has hindered its further applications. Fortunately, the utilization of solid polymer electrolytes combined with organic electrode materials is a promising method to prevent dissolution into the electrolyte and improve the cycling performance of SIBs. Thus, we proposed the utilization of a poly(propylene carbonate) (PPC)-based solid polymer electrolyte and cellulose nonwoven with a 3, 4, 9, 10-perylene-tetracarboxylicacid-dianhydride (PTCDA) cathode in an all-solid-state sodium battery (ASSS). The solid electrolyte significantly enhanced the safety of the SIB and was successfully synthesized via a facile method. The morphology of the as-prepared solid electrolyte was examined by electron scanning microscopy (SEM). Furthermore, the electrochemical performances of the PTCDA/Na battery with organic-liquid and solid electrolytes at room temperature were compared. The SEM results demonstrated that the solid polymer electrolyte and sodium bis(fluorosulfonyl)imide (NaFSI) were evenly distributed inside the pores of the nonwoven cellulose. The ionic conductivity of the composite solid polymer electrolyte (CSPE) at room temperature was 3.01 × 10^-5 S·cm^-1, suggesting that the CSPE was a promising candidate for commercial applications. In addition, the ASSS showed significantly improved cycling performance at a current density of 50 mAh·g^-1 with a high capacity retention of 99.1%, whereas the discharge capacity of the liquid PTCDA/Na battery was only 24.6mAh·g^-1 after 50 cycles. This indicated that the cycling performance of the PTCDA cathode in the SIB was largely improved by preventing the dissolution of the PTCDA cathode material in the electrolyte. Electrochemical impedance spectroscopy results demonstrated that the CSPE was compatible with the organic cathode electrode.     

Al2O3 coated LiCoO2 as cathode for high-capacity and long-cycling Li-ion batteries

In this study, we fabricated a Al₂O₃ layer coated on the surface of LiCoO₂ by a facile and scale-up sol-gel method. The proper thickness coating can improve the cycling life with the cut-off potential (4.5 V), which capacity retention is~73% after 500 cycles, and enhance the capacity, which shows~180 mAh/g.     

基于一体化正极与电解质膜的高性能固态电池

Lithium ion batteries (LIBs) are becoming the most popular energy storage systems in our society. However, frequently occurring accidents of electrical cars powered by LIBs have caused increased safety concern regarding LIBs. Solid-state lithium batteries (SSLBs) are believed to be the most promising next generation energy storage system due to their better in-built safety mechanisms than LIBs using flammable organic liquid electrolyte. However, constructing the ionic conducting path in SSLBs is challenging due to the slow ionic diffusion of Li ion in solid-state electrolyte, particularly in the case of solid-solid contact between the solid materials. In this paper, we demonstrate the construction of an integrated electrolyte and cathode for use in SSLBs. An integrated electrolyte and cathode membrane is obtained via simultaneous electrospinning and electrospraying of a polyacrylonitrile (PAN) electrolyte and a LiFePO₄ (LFP) cathode material respectively, for the cathode layer, followed by the electrospinning of PAN to prepare the electrolyte layer. The resultant integrated PAN-LFP membrane is flexible. Scanning electron microscopy and energy dispersive X-ray spectroscopy measurement results show that the electrode and electrolyte are in close contact with each other. After the integrated PAN-LFP membrane is filled with a succinonitrile-bistrifluoromethanesulfonimide (SN-LiTFSI) salt mixture, it is paired with a lithium foil metal anode electrode, and the resultant solid-state Li|PAN-LFP cell exhibits limited polarization and outstanding interfacial stability during long term cycling. That is, the Li|PAN-LFP cell presents a specific capacity of 160.8 mAh∙g⁻¹ at 0.1C, and 81% of the initial capacity is maintained after 500 cycles at 0.2C. The solid-state Li|PAN-LFP cell also exhibits excellent resilience in destructive tests such as cell bending and cutting.     

基于钴酸锂载体构筑高体积比容量硫基复合材料

锂-硫电池具有高的理论质量/体积能量密度,因而成为最具发展潜力的高比能二次电池体系. 然而,由于硫载体通常采用轻质的碳纳米材料,导致硫基复合材料的振实密度和体积比容量均偏低,制约了电池体积能量密度的提升. 本文尝试采用具有高密度特征的钴酸锂(LiCoO₂)作为硫的载体材料,以构筑高振实密度的硫基复合材料,进而提高硫正极的体积比容量. 研究显示,LiCoO₂对可溶性多硫化物具有较强的吸附作用,能够促进硫的电化学转化,因而提高了硫的活性物质利用率和循环稳定性. 同时,由于具有高的振实密度(1.90 g·cm^-3),S/LiCoO₂复合材料的首周体积比容量高达1750.5 mAh·cm^-3,是常规硫/碳复合材料的2.2倍. 因此,本文利用具有高密度特征的LiCoO₂作为硫载体来提升硫复合材料的体积比容量,有助于实现锂-硫电池的高体积能量密度.