凝胶聚合物电解质双电层电容器的研究

为解决凝胶聚合物电解质制成膜的双电层电容器中,电解质与电极真实表面积接触较差的问题,采用内聚合法制备了以活性炭为电极材料,丙烯腈为聚合单体,ζ(碳酸甲乙酯∶碳酸乙烯酯)=1∶1为增塑剂,高氯酸锂为导电盐的凝胶聚合物电解质双电层电容器。测试结果表明,随着丙烯腈含量的降低,其组成的凝胶聚合物电解质的电导率增大,电容器的比容量也随之增大,当w(丙烯腈)为10%时,室温电导率为9.34×10–3S·cm–1,比容量为24.294F/g。     

有机电解液MnO2/AC混合电容器的研究

固相合成法制备了MnO2电极材料,以其为正极,活性炭(AC)电极为负极,组装了有机电解液MnO2/AC混合电容器。测试结果表明,在1 mol/L的有机电解液LiPF6/(DMC+EC)中,混合电容器的工作电压可达2.5 V,在不同的电流密度下,比容量为43.64～53.17 F/g,漏电流为0.08×10–3 A/cm2,经1 000次恒流充放电循环后,比容量衰减幅度约为8%。     

基于有机-无机复合固态电解质膜的全固态锂电池制备与性能研究

在聚合物电解质中添加Li_7La_3Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)粉体可以降低聚合物材料的结晶度,促进锂离子迁移,进而提高固态电解质的离子电导率。以双三氟甲基磺酸亚酰胺锂(LiTFSI)、聚偏氟乙烯-六氟丙烯(PVDF-HFP)以及LLZTO粉体为原料制备了不同LLZTO含量的氧化物-聚合物复合固态电解质。研究发现,添加质量分数20%LLZTO的固态电解质具有较高的离子电导率以及高机械强度,同时具有更宽的电化学窗口(5.5 V)。所制备的复合正极/固态电解质/复合负极全固态锂离子软包电池首次充放电比容量分别为176.32和143.31 mAh/g,首次库伦效率为81.3%,25次循环后电池放电容量保持率维持在93%以上。此外,循环前后阻抗变化较小,表现出较好的界面稳定性。     

超级电容器用季铵盐凝胶聚合物电解质的制备及性能

采用溶液浇注法,以聚丙烯腈(PAN)为聚合物基体,四乙基四氟硼酸铵(TEABF_4)为电解质盐,二甲基亚砜(DMSO)为增塑剂制备PAN/TEABF_4凝胶聚合物电解质。采用红外光谱(FT-IR)、热重分析(TG-DTG)以及电导率、循环伏安和恒流充放电等电化学性能测试方法,探究不同的TEABF_4与PAN质量配比对PAN/TEABF_4凝胶聚合物电解质性能的影响。当TEABF_4与PAN质量比为0.5时所制得凝胶聚合物电解质性能最佳:电导率为5.583×10~(–3)S/cm、比电容为27.59 F/g、充放电效率为86.63%、能量密度为100.58 J/g、功率密度为0.675×103 W/kg。     

二步聚合工艺在固体钽电容器生产中的应用

采用二步聚合工艺,在固体钽电解电容器阳极体上被覆具有高电导率、热稳定性好的导电聚合物PEDT(聚3,4-乙烯二氧噻吩)取代了MnO2阴极层,研究了工艺参数对电容器性能的影响。结果显示:电容器的tanδ和Res随聚合温度增加而增加;低含量的氧化剂(质量分数20%)有较好容量引出效果,高含量的氧化剂(对甲基苯磺酸铁正丁醇溶液)(40%)可以有效增加电容器外层聚合物的沉积。     

用于柔性超级电容器的多孔有机大分子复合凝胶电解质

通过选择性溶解法制备了多孔结构的聚乙烯醇(PVA)基大分子羧甲基纤维素(CMC)复合凝胶电解质,以此提高凝胶电解质的离子电导率和柔性超级电容器的电化学性能。使用扫描电子显微镜(SEM)对凝胶电解质的形貌进行了表征。凝胶内部为多孔的网络结构,不规则的孔均匀分布在PVA基体中。同时,采用活性炭作为电极组装成柔性超级电容器。对凝胶电解质的离子电导率、吸水率和热稳定性进行了测试,实验结果表明多孔PVA-10%CMC复合凝胶电解质离子电导率最高可达64.3 mS/cm,具有130.3%的吸水率和63.8%的保水率,并且在-10、25和40℃温度梯度下可以稳定使用。此外,利用其组装的柔性超级电容器的比电容最高可达40.0 F/g,循环10 000圈后的比电容保持率为55%,并且有优异的倍率性能和弯曲性能。因此,多孔结构的构建和CMC的复合是提高凝胶电解质性能的有效方法。     

掺CeO2纳米MnO2非对称超级电容器的研究

采用化学共沉淀法制备出超级电容器用掺CeO2的MnO2电极材料,通过XRD、SEM对样品进行了表征,研究了掺杂量对MnO2电极稳定性能的影响。结果表明,产物主相为α-MnO2,粒度分布较均匀,在50～100nm;在6mol/L的KOH电解液中,该掺杂MnO2电极材料具有优良的电容行为和循环稳定性能。当掺CeO2量为10%(与MnO2的质量比)时,在电流密度为250mA/g时,比电容量达257.68F/g;循环500次,容量仅衰减1.18%。     

热处理对纳米α-MnO2电容特性的影响

采用化学沉淀法制备出超级电容器用纳米MnO2电极材料,研究了热处理工艺对MnO2电容性能的影响。结果表明,产物主相为α-MnO2,粒度分布较均匀,在50～100 nm;热处理温度和时间对MnO2的电容性能有着重要影响。将在300℃热处理3 h的MnO2与活性炭电极组成非对称超级电容器,循环充放电500次,容量仅衰减2.24%;在电流密度为500 mA/g时,比电容量达302.52 F/g。     

碳纳米管作为超大容量离子电容器电极的研究

本文采用碳纳米管作为超大容量离子电容器的电极材料,研究了硝酸改性处理、粘结剂对电极的电容器性能的影响,探讨了其电容的形成机理.当用硝酸改性处理的碳纳米管作电极,用30%(wt)的H₂SO₄作电解质溶液时,所得超大容量离子电容器不仅能形成双电层电容,也能形成赝电容,从而得到了69F/g的比电容;同时碳纳米管电极超大容量离子电容器具有良好的频率响应特性.     

超级电容器新型复合电极材料MnO_2/活性MCMB的研究

以Mn(NO3)2、活性中间相碳微球(活性MCMB)为原料,采用KBrO3氧化法,成功制备了MnO2/活性MCMB新型复合电极材料;以该材料制成电极,并以质量分数为30%的KOH溶液为电解液,组装成扣式电容器。通过XRD和SEM分析了MCMB,活性MCMB及MnO2/活性MCMB的晶相结构和表面形态;采用循环伏安、交流阻抗和恒流充放电法研究了电容器的电容性能。结果表明:以MnO2/活性MCMB复合电极制成的电容器电容性能优良。在0.5A/g电流密度下,其充放电曲线表现出典型的电容行为,初始比容量高达403.5F/g,相应能量密度为12.5Wh/kg;其循环伏安曲线关于零电流线对称,呈现为较规则的矩形;其等效串联电阻约为0.7Ω。     

Improving electroactive polymer actuator by tuning ionic liquid concentration

We have fabricated actuators from a blend of fluoropolymer (FP) with ionic liquid (IL). Here a combination of graphene, graphite, and silver nanoparticles is used to raise the electrode conductivity. As the electrode composition is fixed, we found that the actuator displacement increases with decreasing amount of ionic liquid in the polymer gel electrolyte. A maximum strain of 0.48% was observed from peak-to-peak displacement for an actuator with IL/FP = 0.3 in the polymer gel electrolyte. The simulation results indicate that lowering IL concentration leads to a more compact ion distribution in the electrode layers and hence explains the increased strain in the actuators.     

A Structurable Gel‐Polymer Electrolyte for Sodium Ion Batteries

In this work, a structurable gel‐polymer electrolyte (SGPE) with a controllable pore structure that is not destroyed after immersion in an electrolyte is produced via a simple nonsolvent induced phase separation (NIPS) method. This study investigates how the regulation of the nonsolvent content affects the evolving nanomorphology of the composite separators and overcomes the drawbacks of conventional separators, such as glass fiber (GF), which has been widely used in sodium ion batteries (SIBs), through the regulation of pore size and gel‐polymer position. The interfacial resistance is reduced through selective positioning of a poly(vinylidene fluoride‐co‐hexa fluoropropylene) (PVdF‐HFP) gel‐polymer with the aid of NIPS, which in turn enhances the compatibility between the electrolyte and electrode. In addition, the highly porous morphology of the GF/SGPE obtained via NIPS allows for the absorption of more liquid electrolyte. Thus, a greatly improved cell performance of the SIBs is observed when a tailored SGPE is incorporated into the GF separator through charge/discharge testing compared with the performance observed with pristine GF and conventional GF coated with PVdF‐HFP gel‐polymer.     

Efficient gel-state dye-sensitized solar cells adopting polymer gel electrolyte based on poly(methyl methacrylate)

We report an effective method to fabricate gel-state dye-sensitized solar cells (DSSCs) based on the PMMA polymer gel electrolyte. In this approach, the liquid-state polymer electrolyte solution was prepared by simply mixing the traditional liquid-state electrolyte with the polymer gelator solution and was injected into the DSSC in its liquid state. The liquid-state polymer electrolyte was then converted to the gel state (i.e., in situ gelation) simply by evaporating a portion of solvents at elevated temperatures. With this approach, liquid electrolytes already well developed and optimized for DSSCs can be readily adopted. Filling in the liquid/solution state ensures effective penetration of the electrolyte into pores of TiO₂ nanoparticle electrodes for attaining good contact and interface properties. The in situ gelation by heating (solvent evaporation) much simplifies the process. The polymer gel electrolyte thus prepared exhibited high ion conductivity and diffusivity comparable to those of traditional liquid electrolytes. The gel-state DSSCs thus fabricated exhibited a high power-conversion efficiency of 8.03% and much improved stability compared to the traditional liquid DSSC.     

导电高分子钽电解电容器的研究进展

综述了导电高分子钽电解电容器的最新研究进展。比较了导电高分子钽电解电容器和二氧化锰钽电解电容器在结构、制造工艺和性能方面的差别。还介绍了聚吡咯(PPy)、聚乙撑二氧噻吩(PEDOT)和聚苯胺(PANi)钽电解电容器的研究状况。导电高分子膜的形成工艺对钽电解电容器性能影响很大。改进和开发新型阴极材料是降低钽电解电容器等效串联电阻Res的重要途径。     

Multi‐Functional Dual‐Layer Polymer Electrolytes for Lithium Metal Polymer Batteries

We prepared a novel multi‐functional dual‐layer polymer electrolyte by impregnating the interconnected pores with an ethylene carbonate (EC)/dimethyl carbonate (DMC)/lithium hexafluorophosphate (LiPF₆) solution. The first layer, based on a microporous polyethylene, is incompatible with a liquid electrolyte, and the second layer, based on poly (vinylidenefluoride‐co‐hexafluoropropylene), is submicroporous and compatible with an electrolyte solution. The maximum ionic conductivity is 7 × 10^?3 S/cm at ambient temperature. A unit cell using the optimum polymer electrolyte showed a reversible capacity of 198 mAh/g at the 500th cycle, which was about 87% of the initial value.     

Ambient-Temperature All-Solid-State Sodium Batteries with a Laminated Composite Electrolyte

This study presents a sodium-ion conductive laminated polymer/ceramic-polymer solid-state electrolyte for the development of room-temperature all-solid-state sodium batteries. At the negative electrode side, a negative-electrode-benign poly(ethylene oxide) (PEO) is used as a polymer matrix into which succinonitrile (SN) is integrated to improve the room-temperature Na⁺-ion conductivity. At the positive electrode side, a cathode-friendly poly(acrylonitrile) (PAN) serves as a polymer matrix into which a NASICON-type ceramic solid-electrolyte (Na₃Zr₂Si₂PO₁₂) powder is incorporated toward both the enhancement of Na⁺-ion conductivity and the prevention of Na dendrite from penetrating through the electrolyte membrane. Through a strategical management of composition, the PAN-Na₃Zr₂Si₂PO₁₂-NaClO₄ composite and the PEO-SN-NaClO₄ polymer deliver a balanced Na⁺-ion conductivity. Combining the two electrolyte layers, the laminated PEO-SN-NaClO₄/PAN-Na₃Zr₂Si₂PO₁₂-NaClO₄ solid electrolyte provides a Na⁺-ion conductivity of 1.36 × 10⁻⁴ S cm⁻¹ at room temperature. With respect to the anodic friendly feature of the PEO-SN-NaClO₄ layer and the cathodic friendly feature of the PAN-Na₃Zr₂Si₂PO₁₂-NaClO₄ layer, the laminated solid electrolyte presents a stable electrochemical window of 0–4.8 V. Room-temperature all-solid-state sodium batteries fabricated with the laminated solid electrolyte, a Na-metal negative electrode, and a Na₂MnFe(CN)₆ positive electrode exhibit remarkably stable cyclability.