大容量碳纳米管极板双电层电容器的研制

碳纳米管具有良好的导电性和合适的孔径分布以及较高的比表面积。选用聚四氟乙烯(PTFE)作为碳纳米管极板的粘结剂,网络结构的泡沫镍作为集流体,在有机电解质溶液中,通过直流充放电、恒功率充放电、循环伏安特性和自放电测试等实验,显示了本实验室制备的碳纳米管材料组装的双电层电容器具有良好的电化学性能。电容器中碳纳米管比电容量达74.1 F/g,比能量达16.1 Wh/kg,在自放电特性测试过程中,电容器漏电流稳定在2 mA左右。     

碳纳米管–聚吡咯复合材料在超电容器中的应用

在碳纳米管(CNT)基体上用化学聚合或电化学聚合方法沉积聚吡咯(PPy)制得复合材料。再以此类复合材料为活性物质制作电极,组装成原型超电容器。并对其进行了循环伏安、恒电流充放电等电化学测试。用此类复合材料制成的原型超电容器的比容量(23.6 F/g)与纯碳纳米管(2.3 F/g)或纯聚吡咯(3.9 F/g)制成的原型电容器比较,发现复合电极电容器比容量的提高不是简单的加和效应,而是协同效应所致。     

碳纳米管–聚吡咯复合材料在超电容器中的应用

在碳纳米管(CNT)基体上用化学聚合或电化学聚合方法沉积聚吡咯(PPy)制得复合材料。再以此类复合材料为活性物质制作电极,组装成原型超电容器。并对其进行了循环伏安、恒电流充放电等电化学测试。用此类复合材料制成的原型超电容器的比容量(23.6 F/g)与纯碳纳米管(2.3 F/g)或纯聚吡咯(3.9 F/g)制成的原型电容器比较,发现复合电极电容器比容量的提高不是简单的加和效应,而是协同效应所致。     

电子元件、组件

TM53 2004020521碳纳米管超电容器组装工艺的初步探讨/王晓峰,王大志,梁吉(清华大学)11电源技术一2003,27(5)一451一454通过催化裂解法制备了碳纳米管并采用超声震荡的方法制备成板式碳纳米管电极碳纳米管材料比容量为39F·g一1,并表现出良好的功率特性.阻抗测试表明球模处理可以较明显地降低碳纳米管材料的电阻.采用多种研究方法对基于该种材料的超电容器的电化学特性进行了详细研究,并采用“Transmission line model’,模型对电极的多孔结构进行了模拟还介绍了两种超电容器组装工艺并根据该工艺制备了工型和H型碳纳米管超电容器,两种超…     

超级电容器混合型电解液(EMIES+LiClO_4)的热力学和电化学性质

介绍了一种新型离子液体混合电解质(液),由离子液体1-乙基-3-甲基咪唑硫酸乙酯盐(EMIES)与高氯酸锂盐按照不同配比混合制备而成。测定了这种新型混合电解质(EMIES+Li Cl O_4)的一系列热力学性质,如:电导率、密度、表面张力等,发现其黏度和电导率随温度的变化呈相反趋势。锂盐的加入带来了混合电解液电导率的非线性变化,而当其中高氯酸盐的摩尔比为0.05时,电解液具有最佳电导率和黏度。进而,用此浓度的混合电解液与活性炭电极组装成超级电容器,采用交流阻抗、恒流充放电及循环伏安等测试手段对其性能进行测试与研究。结果表明:这种离子液体混合电解液电化学窗口达到5.1 V,单电极比电容为458.65 F·cm~(-3),充放电测试1000次以后,比电容只下降了1.9%。表明该混合电解液具有良好的电容特性、可逆性及循环特性,具备成为高性能超级电容器电解液的应用潜力。     

铝电解电容器的季铵有机工作电解液

合成了新型电解质材料——四烷基铵盐(季铵盐),给出了该类电解质材料的基本性质;研究并讨论了非水有机溶剂-季铵盐系统工作电解液的基础性质;对采用该电解液系统的电容器(50V-33μF)进行了105℃、1000h的贮存寿命试验和工作寿命试验,并与传统高温工作电解液进行了对比分析,证实了该类电解质的化学、电化学稳定性。该类电解质适用于宽温或高温长寿命铝电解电容器。     

20伏高电压型碳纳米管超级电容器的研制

通过催化裂解法制备了碳纳米管并进一步制备了碳纳米管膜片式电极.基于该种材料的超级电容器电极比容量达到42F/g并表现出良好的大电流放电特性.本文采用多种研究方法对基于该种材料的双电层电容器的电化学特性进行了详细的研究.本文还开发了全新的超级电容器组装工艺,采用该工艺组装的碳纳米管超级电容器工作电压可以达到20V并具有良好的容量特性和阻抗特性.     

超级电容器用LiBOB电解质电化学性能的研究

以草酸、硼酸及氢氧化锂为原料,通过水相中发生酯化反应和在乙腈中进行中和反应结合的方法合成LiBOB(双草酸硼酸锂)。通过电导率、循环伏安、恒电流充放电、交流阻抗等电化学性能测试方法,探索溶剂组成、LiBOB浓度及商业主流电解质盐Et_4NBF_4添加量对LiBOB电解液电化学性能的影响。以LiBOB电解质盐不同溶剂组成的电解液组装的模拟碳超级电容器,工作电压范围在0~2.7 V,循环伏安曲线出现了类矩形的特征;充放电可逆性及电化学循环稳定性良好。LiBOB-Et_4NBF_4工作电解液的电导率最优可达12.5×10~(–3) S/cm。     

1-丁基-3-甲基咪唑离子液体在超级电容器中的应用

两步法合成了1-丁基-3-甲基咪唑三氟乙酸盐(BMI-CF3CO2)、1-丁基-3-甲基咪唑六氟磷酸盐(BMI-PF6)及1-丁基-3-甲基咪唑四氟硼酸盐(BMI-BF4)三种离子液体,研究了这三种离子液体所制超级电容器的电化学性能。结果表明:BMI-CF3CO2在电化学稳定性及充放电效率等方面优于BMI-PF6和BMI-BF4;BMI-CF3CO2离子液体电解液电势窗口达到4.0V,所制备的超级电容器在3.6V电压下循环寿命超过1000次。     

三氟乙酸离子液体/四氟硼酸螺环季铵盐混合电解液的超级电容性质研究

采用两步法合成功能化离子液体1-甲基-3-丁基咪唑三氟乙酸盐离子液体([Bmim][CF_3CO_2]),并将其与有机电解质四氟硼酸螺环季铵盐([(C_4H_8)_2N][BF_4])组成不同浓度配比的新型混合电解液。采用活性炭为电极,组装成超级电容器,通过循环伏安、恒流充放电、交流阻抗等方法对其电化学性能进行了研究。结果显示:混合电解液的浓度为2.06 mol/L时的性能最优,这种新型的混合电解液25℃时电导率为3.99×10~(–3) S/cm,电化学窗口可达2.7 V,内阻0.96?,经过1 000次充、放电循环后仍可保留98%的初始比电容,说明该混合电解液具有突出的电化学性能和巨大的市场应用潜力。     

活性炭前处理对双电层电容器性能的影响

制备了沥青焦基活性炭双电层电容器用电极材料,将其分别经水洗、酸洗以及超音速气流粉碎处理。在1 mol/L(C2H5)4NBF4/碳酸丙烯酯电解液体系中进行电化学测试,对比评价了各活性炭前处理方法对电容器电化学性能的影响。结果表明,酸洗后活性炭电极比电容提高7%达到163 F/g,高功率放电性能明显改善,当电流密度由70 mA/g增加到1 A/g时,其电极比电容保持率为88%;活性炭进行超细粉碎后不利于电化学性能的提高。     

LiNi1/3Co1/3Mn1/3O2/AC混合超级电容器正负极容量配比研究

采用1 mol/L的LiBF4/AN(CH3CN)为电解液,对LiNi1/3Co1/3Mn1/3O2/AC体系混合超级电容器进行了电化学性能对比研究.通过优化正负极的容量配比,分别评价了对应的超级电容器的充放电性能、倍率性能和循环寿命.结果表明,在正负极容量配比为4:1时,该体系超级电容器的比能量为11 Wh/kg、比...     

Enhanced Ionic/Electronic Transport in Nano‐TiO2/Sheared CNT Composite Electrode for Na+ Insertion‐based Hybrid Ion‐Capacitors

Ion‐insertion capacitors show promise to bridge the gap between supercapacitors of high power densities and batteries of high energy densities. While research efforts have primarily focused on Li⁺‐based capacitors (LICs), Na⁺‐based capacitors (SICs) are theoretically cheaper and more sustainable. Owing to the larger size of Na⁺ compared to Li⁺, finding high‐rate anode materials for SICs has been challenging. Herein, an SIC anode architecture is reported consisting of TiO₂ nanoparticles anchored on a sheared‐carbon nanotubes backbone (TiO₂/SCNT). The SCNT architecture provides advantages over other carbon architectures commonly used, such as reduced graphene oxide and CNT. In a half‐cell, the TiO₂/SCNT electrode shows a capacity of 267 mAh g^?1 at a 1 C charge/discharge rate and a capacity of 136 mAh g^?1 at 10 C while maintaining 87% of initial capacity over 1000 cycles. When combined with activated carbon (AC) in a full cell, an energy density and power density of 54.9 Wh kg^?1 and 1410 W kg^?1, respectively, are achieved while retaining a 90% capacity retention over 5000 cycles. The favorable rate capability, energy and power density, and durability of the electrode is attributed to the enhanced electronic and Na⁺ conductivity of the TiO₂/SCNT architecture.     

碳纳米管-氢氧化镍复合电极电化学电容器

采用催化裂解法制备了碳纳米管并进一步制备了碳纳米管薄膜电极。基于该种材料的超电容器电极比容量为36 F/g。研究了在碳纳米管薄膜基体上使用电化学方法沉积氢氧化镍的新工艺,制备出碳纳米管/氢氧化镍复合电极。伏安特性曲线以及直流充放电实验证明复合电极的单电极比容量达到63 F/g,交流阻抗谱证明复合电极具有优良的阻抗特性。     

Synthesis and Rate Performance of Monolithic Macroporous Carbon Electrodes for Lithium‐Ion Secondary Batteries

Three‐dimensionally ordered macroporous (3DOM) materials are composed of well‐interconnected pore and wall structures with wall thicknesses of a few tens of nanometers. These characteristics can be applied to enhance the rate performance of lithium‐ion secondary batteries. 3DOM monoliths of hard carbon have been synthesized via a resorcinol‐formaldehyde sol–gel process using poly(methyl methacrylate) colloidal‐crystal templates, and the rate performance of 3DOM carbon electrodes for lithium‐ion secondary batteries has been evaluated. The advantages of monolithic 3DOM carbon electrodes are: 1) solid‐state diffusion lengths for lithium ions of the order of a few tens of nanometers, 2) a large number of active sites for charge‐transfer reactions because of the material's high surface area, 3) reasonable electrical conductivity of 3DOM carbon due to a well‐interconnected wall structure, 4) high ionic conductivity of the electrolyte within the 3DOM carbon matrix, and 5) no need for a binder and/or a conducting agent. These factors lead to significantly improved rate performance compared to a similar but non‐templated carbon electrode and compared to an electrode prepared from spherical carbon with binder. To increase the energy density of 3DOM carbon, tin oxide nanoparticles have been coated on the surface of 3DOM carbon by thermal decomposition of tin sulfate, because the specific capacity of tin oxide is larger than that of carbon. The initial specific capacity of SnO₂‐coated 3DOM carbon increases compared to that of 3DOM carbon, resulting in a higher energy density of the modified 3DOM carbon. However, the specific capacity decreases as cycling proceeds, apparently because lithium–tin alloy nanoparticles were detached from the carbon support by volume changes during charge–discharge processes. The rate performance of SnO₂‐coated 3DOM carbon is improved compared to 3DOM carbon.     

A Novel Moisture‐Insensitive and Low‐Corrosivity Ionic Liquid Electrolyte for Rechargeable Aluminum Batteries

Rechargeable aluminum batteries (RABs) are extensively developed due to their cost‐effectiveness, eco‐friendliness, and low flammability and the earth abundance of their electrode materials. However, the commonly used RAB ionic liquid (IL) electrolyte is highly moisture‐sensitive and corrosive. To address these problems, a 4‐ethylpyridine/AlCl₃ IL is proposed. The effects of the AlCl₃ to 4‐ethylpyridine molar ratio on the electrode charge–discharge properties are systematically examined. A maximum graphite capacity of 95 mAh g^?1 is obtained at 25 mA g^?1. After 1000 charge–discharge cycles, ≈85% of the initial capacity can be retained. In situ synchrotron X‐ray diffraction is employed to examine the electrode reaction mechanism. In addition, low corrosion rates of Al, Cu, Ni, and carbon‐fiber paper electrodes are confirmed in the 4‐ethylpyridine/AlCl₃ IL. When opened to the ambient atmosphere, the measured capacity of the graphite cathode is only slightly lower than that found in a N₂‐filled glove box; moreover, the capacity retention upon 100 cycles is as high as 75%. The results clearly indicate the great potential of this electrolyte for practical RAB applications.     

Drawing a Pencil‐Trace Cathode for a High‐Performance Polymer‐Based Li–CO2 Battery with Redox Mediator

Lithium–carbon dioxide (Li–CO₂) batteries have received wide attention due to their high theoretical energy density and CO₂ capture capability. However, this system still faces poor cycling performance and huge overpotential, which stems from the leakage/volatilization of liquid electrolyte and instability of the cathode. A gel polymer electrolyte (GPE)‐based Li–CO₂ battery by using a novel pencil‐trace cathode and 0.0025 mol L^?1 (M) binuclear cobalt phthalocyanine (Bi‐CoPc)‐containing GPE (Bi‐CoPc‐GPE) is developed here. The cathode, which is prepared by pencil drawing on carbon paper, is stable because of its typical limited‐layered graphitic structure without any binder. In addition, Bi‐CoPc‐GPE, which consists of polymer matrix filled with liquid electrolyte, exhibits excellent ion conductivity (0.86 mS cm^?1), effective protection for Li anode, and superior leakproof property. Moreover, Bi‐CoPc acts as a redox mediator to promote the decomposition of discharge products at low charge potential. Interestingly, different from polymer‐shaped discharge products formed in liquid electrolyte–based Li–CO₂ batteries, the morphology of products in Li–CO₂ batteries using Bi‐CoPc‐GPE is film‐like. Hence, this polymer‐based Li–CO₂ battery shows super‐high discharge capacity, low overpotential, and even steadily runs for 120 cycles. This study may pave a new way to develop high‐performance Li–CO₂ batteries.     

PMMA基凝胶聚合物电解质MnO2电容器的研究

以沉淀法制备的MnO2为正极材料,活性炭(AC)为负极材料,甲基丙烯酸甲酯(MMA)作聚合物单体,碳酸二甲酯(DMC)与碳酸乙烯酯(EC)的混合液作增塑剂,高氯酸锂为支持电解质,采用内聚合法制备PMMA基凝胶聚合物电解质MnO2/AC混合电容器。测试结果表明,随着MMA含量的降低,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MMA的含量为20%时,凝胶聚合物电解质的电导率可达6.1×10–3S/cm,比容量为34.02F/g。     

Design and Synthesis of Hierarchical Nanowire Composites for Electrochemical Energy Storage

Nanocomposites of interpenetrating carbon nanotubes and vanadium pentoxide (V₂O₅) nanowires networks are synthesized via a simple in situ hydrothermal process. These fibrous nanocomposites are hierarchically porous with high surface area and good electric conductivity, which makes them excellent material candidates for supercapacitors with high energy density and power density. Nanocomposites with a capacitance up to 440 and 200 F g^?1 are achieved at current densities of 0.25 and 10 A g^?1, respectively. Asymmetric devices based on these nanocomposites and aqueous electrolyte exhibit an excellent charge/discharge capability, and high energy densities of 16 W h kg^?1 at a power density of 75 W kg^?1 and 5.5 W h kg^?1 at a high power density of 3 750 W kg^?1. This performance is a significant improvement over current electrochemical capacitors and is highly competetive with Ni–MH batteries. This work provides a new platform for high‐density electrical‐energy storage for electric vehicles and other applications.     

氧化改性Ni(OH)2的电化学电容特性研究

为获得高比电容量电极材料,制备出氧化改性Ni(OH)2,并对样品进行了XRD和XPS分析,通过恒流充放电测试分析了氧化改性Ni(OH)2/活性炭非对称型电化学电容器的电容特性,讨论了活性炭与氧化改性Ni(OH)2质量比对比电容量的影响。结果表明,氧化改性Ni(OH)2电容器性能稳定,稳定工作电压可达1.60V;在活性炭与氧化改性Ni(OH)2质量比约为2.7时,比电容量高达93.78F/g。