微型超级电容器PPy/GO-RuO<sub>2</sub>复合膜电极的制备与电化学性能

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朱平, 蔡婷, 韩高义, 熊继军. 微型超级电容器PPy/GO-RuO₂复合膜电极的制备与电化学性能 . 无机材料学报, 2015, 30(5): 505-510
ZHU Ping, CAI Ting, HAN Gao-Yi, XIONG Ji-Jun. Preparation and Electrochemical Performance of PPy/GO-RuO₂Film Electrode for Micro-supercapacitor . Journal of lnorganic Materials,2015, 30(5): 505-510 复制到剪切板

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微型超级电容器PPy/GO-RuO₂复合膜电极的制备与电化学性能

朱平^1,², 蔡婷^1,², 韩高义³, 熊继军^1,²

1. 中北大学电子测试技术重点实验室, 太原 030051

2. 中北大学仪器与电子学院, 太原 030051

3. 山西大学分子科学研究所, 太原 030006

作者简介: 朱平(1976-), 女, 博士. E-mail: h.zhuping@163.com

基金:山西省自然科学基金(2012011010-2)

摘要

为了解决氧化钌(RuO₂)沉积电位过高, 难以在三维微结构金属集流体上直接沉积的问题, 提出采用分步电沉积方法在微三维结构镍(Ni)集流体上制备RuO₂复合膜电极, 即先在三维微结构Ni集流体上沉积聚吡咯/氧化石墨烯(PPy/GO)薄膜作为基底, 经热处理后, 在基底上二次沉积出RuO₂颗粒, 最后再对RuO₂复合薄膜进行二次热处理。扫描电子显微镜(SEM)观察显示, 随着热处理温度的升高, 薄膜表面多孔结构增多, 达到了提高膜电极结构孔隙分布的目的。能量分散谱(EDS)和X射线光电子能谱分析(XPS)表明, 薄膜中无定形RuO₂· xH₂O的存在保证了膜电极的大比容量。电化学性能测试结果表明, 经105℃处理后的膜电极电化学性能最佳, 比电容为28.5 mF/cm², 能量密度为0.04 Wh/m², 功率密度为14.25 W/m²。采用分步电沉积方法制备出的RuO₂复合薄膜是一种良好的MEMS超级电容器电极材料。

关键词: RuO2复合薄膜; 分步电沉积; 热处理; MEMS超级电容器

中图分类号:TQ174 文献标志码:A 文章编号:1000-324X(2015)05-0505-06

Preparation and Electrochemical Performance of PPy/GO-RuO₂Film Electrode for Micro-supercapacitor

ZHU Ping^1,², CAI Ting^1,², HAN Gao-Yi³, XIONG Ji-Jun^1,²

1. Science and Technology on Electronic Test & Measurement Laboratory, North University of China, Taiyuan 030051, China

2. North University of China, School Instrument and Electronics, Taiyuan 030051, China

3. Shanxi Laboratory for Molecular Sciences, Shanxi University, Taiyuan 030006, China

Fund:Natural Science Foundation of Shanxi Province(2012011010-2)

Abstract

To address the issue that RuO₂ was difficult to deposit directly on the micro-3D-structure metal current collector due to its high deposition potential, this study was engaged to prepare RuO₂ composite film by the fractional electro-deposition method. PPy/GO film was firstly deposited on nickel current collector as substrate, then RuO₂ particles were deposited on the substrate after heat-treatment, finally the RuO₂ composite film was carried on a second heat-treatment. By means of scanning electron microscope (SEM), it can be found that the porous structures of RuO₂ composite film multiply with the increase of heat-treatment temperature, so that the pore structure of the membrane electrode is improved. By means of X-ray energy dispersive spectroscope (EDS) and X-ray photoelectron spectroscope (XPS), the results indicate that there exists amorphous RuO₂· xH₂O in the film, which ensures the great specific capacity of the membrane electrode. The electrochemical testing results indicate that the electrochemical performance of membrane electrode is optimal when heat-treatment temperature reaches 105℃, with specific capacitance of 28.5 mF/cm², energy density of 0.04 Wh/m² and power density of 14.25 W/m². The RuO₂ composite film prepared by using step-by-step electro-deposition method is a type of excellent electrode material for micro-supercapacitor.

Keyword: RuO2 composite films; step-by-step electro-deposition; heat treatment; micro-supercapacitor

Show Figures

膜电极的电化学性能决定着超级电容器的储能特性, 膜电极的材料选用及其可控制备, 仍然是MEMS超级电容器研制的关键。相关研究工作主要分为两类^{[1, 2, 3, 4, 5, 6, 7]}: (1)最大程度提高膜材料的比表面积, 开发每平方厘米或每克能实现的最大双电层电容; (2)最大程度减小三维微结构所占用表观面积的同时提高能量密度。研制大功率密度及大能量密度MEMS超级电容器, 对高比表面积膜材料的需求很大, 但它不是决定电容器特性的唯一因素。其他因素也参与优化电极结构, 如: 膜材料结构中孔隙尺寸分布。实际的孔隙尺寸分布极大地取决于功能材料的来源及其预处理, 如: 常规膜材料设计一般选用碳系材料(如CNT)、氧化还原氧化物(如RuO₂), 或者活性聚合物(如PPy)等功能材料来实现^{[8, 9, 10, 11]}; 功能材料预处理一般是对合成聚合物(如丙烯腈C₃H₃N)进行碳化, 或者对天然有机物(如椰子壳)进行碳化^{[12, 13, 14]}。

目前, MEMS超级电容器膜电极材料主要包括: 碳系列材料、金属氧化物和导电聚合物^[15]。在各种膜电极材料中, 无定形水合氧化钌(RuO₂· xH₂O)不仅具有较大的理论比容量(> 1000 F/g), 而且具有较高的电导率(> 100 S/cm)和良好的循环稳定性^[16], 适合用于超级电容器。制备RuO₂膜电极材料的常规方法主要有: 热分解氧化法、溶胶-凝胶法和电沉积法, 前两种制备方法不适用于三维微结构金属集流体表面沉积, 而采用电沉积法不仅可以沉积RuO₂, 而且还能避免添加粘结剂与导电剂导致的电化学性能降低等问题。然而, 采用电沉积法在微米级的集流体三维结构上沉积RuO₂却有两个难点: (1)由于RuO₂沉积电位较高, 难以在金属集流体表面直接沉积^{[17, 18]}; (2)由于Ru是一种贵金属材料, 需要在RuO₂中掺杂其他材料来降低成本。通常的解决方法是在RuO₂中掺杂石墨等材料来减少RuO₂用量, 从而提高Ru的利用率和膜材料比容量^{[19, 20]}。如, Hu等^[20]通过电化学剥离法先在石墨棒表面构筑有序的二维石墨纳米片阵列, 再采用阴极还原法在阵列表面均匀包覆一层RuO₂薄膜形成的复合膜电极效果最佳, 比容量高达4226 F/m²。然而在MEMS超级电容器微米级的集流体三维结构上构筑以有序石墨纳米片阵列为基底的RuO₂复合膜电极, 却特别容易出现阴阳极黏连和接触等失效现象。因此, Hu等^[20]的制备方法不适用于MEMS超级电容器。为此, 本研究采用分步电沉积方法, 在三维微结构Ni集流体上, 制备以聚吡咯/氧化石墨烯(PPy/GO)薄膜为基底的RuO₂复合膜电极, 即先在三维微结构上沉积PPy/GO薄膜作为基底, 分别经25、65和105℃热处理后, 在基底上再沉积RuO₂· xH₂O, 最后在对应温度下二次热处理得到RuO₂复合薄膜, 实现适用于MEMS超级电容器的膜电极可控制备。

1 实验方法

1.1 试剂

水合三氯化钌(RuCl₃· xH₂O), aladdin牌, 质量含量为38%~42%; 氧化石墨烯水溶液(GO), 中国科学院山西煤炭化学研究所, 质量浓度为2 mg/mL; 吡咯(Py)、苯磺酸钠(BSNa)、硝酸钠(NaNO₃)和氯化钠(NaCl)均为Aladdin牌, 分析纯(AR)。

1.2 分步沉积RuO₂复合膜电极

采用循环伏安法分步沉积RuO₂复合膜电极。

第一步, 制备PPy/GO薄膜, 制备过程为: 用电子天平称取BSNa粉末0.43 g, 加入到83 μ L的Py单体中, 然后加入GO水溶液0.5 mL和去离子水定容至10 mL, 超声分散15 min, 溶液为浅褐色透明。在室温条件下, 采用循环伏安法以三电极体系在三维微结构Ni集流体表面沉积PPy/GO薄膜, 在-0.4~1.0 V扫描电压范围内以100 mV/s扫描速率, 循环伏安扫描56圈, 制备3个PPy/GO薄膜样品, 然后分别在25、65和105℃空气气氛中干燥处理1 h, 留待备用。

第二步, 取NaNO₃固体分别配置1.0和0.5 mol/L的水溶液, 再量取RuCl₃水溶液200 μ L和NaNO₃水溶液100 μ L, 加去离子水定容至10 mL, 超声分散15 min, 溶液呈深褐色。在室温条件下, 采用循环伏安法和三电极体系, 在3个PPy/GO薄膜样品表面沉积RuO₂颗粒, 在-0.7~0.7 V扫描电位范围内以100 mV/s扫描速率, 循环伏安扫描56圈。最后, 将前述3个样品分别置入与第一步对应温度的空气气氛中再次干燥处理1 h, 得到RuO₂复合膜电极样品, 并编号为PGR25、PGR65和PGR105。

1.3 RuO₂复合膜电极测试设备

采用JSM-6700F型扫描电子显微镜观察样品的表面形貌(SEM), 并进行能谱分析(EDS)。采用AXIS ULTRA DLD型X射线光电子能谱仪(XPS)分析样品的表面组成和化学状态。采用CHI660E型电化学工作站, 以三电极体系在0.5 mol/L NaCl电解液中测试样品的循环伏安特性和交流阻抗特性。

2 结果与讨论

2.1 结构表征

图1给出PGR25、PGR65和PGR105样品的SEM图谱和EDS分析结果。从图1中可看出, 不同温度处理后的RuO₂复合薄膜表面形貌发生了明显变化。经25℃处理的PGR25样品表面的球形晶核直径相对较大, 约为600 nm; 经65℃处理的PGR65样品表面的球形晶核直径有所减小, 约为400 nm; 经105℃处理的PGR105样品表面的球形晶核直径进一步缩小, 约为200 nm。这是由于随着热处理温度的升高, RuO₂· xH₂O部分失水, 使得团聚在一起的RuO₂· xH₂O逐步分散而单独成核造成。而随着成核数目增多, RuO₂· xH₂O颗粒均匀地包覆在PPy/GO表面, 并且薄膜表面的多孔结构也随之增多。可以看出, 热处理不仅使RuO₂颗粒均匀分散, 而且有效增大膜结构中的孔隙尺寸分布, 提高电解质进入膜结构孔隙区域的实际分布面积, 从而降低膜材料间的转移电阻。EDS结果显示, 3种样品中均含有C、O和Ru等元素, 表明分步电沉积RuO₂的方法是可行的。

图2(a)、(b)为一次、二次沉积后样品的XPS全扫描谱图。从图2(a)可以看出, 沉积物表层存在C、O、N, 不含Ni元素, 说明样品覆盖较完全。从图2(b)可以看出, 沉积物表层存在C、O、N、Ru, 不含Ni元素, 与EDS测试结果一致, 说明样品覆盖较完全。由于Ru的XPS强峰Ru3d与C1s强峰有重叠, 故在270~295 eV内小范围扫描得到Ru3d图谱(图2(c))。从图2(c)可以看出, Ru3d图谱显示的特征形状为两个相对独立的峰, 分别对应着整合的5/2、3/2自旋轨道成分; Ru3d_5/2强峰呈宽峰型, 强度最大值出现在结合能282 eV处, 与Ru⁴⁺的结合能对应, 但其结合能略高于无水RuO₂(280.7~ 281.0 eV)^[21], 可以认为电沉积法获得的是由多氧化态Ru组成的混合羟基氧化物。因图2(b)中的O1s峰强度明显高于图2(a), 故对O1s峰解叠后得到图谱(图2(d))。从图2(d)可以看出, O1s峰分解为结合能530.2、531.5和532.8 eV三个峰, 其中, 两个低结合能位置的峰(530.2、532.8 eV)分别对应于Ru-O-Ru键和H-O-H键, 531.5 eV处的强峰对应于Ru-OH键^[22]。可以认为随着二次沉积的进行, RuCl₃· xH₂O发生了还原氧化反应, 生成了RuO₂· xH₂O, 使得O1s峰强度增加。薄膜中无定形RuO₂· xH₂O的存在有助于提高比表面积和缩短电子、离子的扩散路径, 使得膜电极的比容量和充放电性能提高。

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	图1 RuO₂复合薄膜SEM图和EDS分析结果Fig. 1 SEM images and EDS analyses of RuO₂ composite films after heat-treatment at different temperatures (a) 25℃; (b) 65℃; (c) 105℃

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	图2 一次沉积(a)和二次沉积(b)样品及其Ru3d(c)和O1s (d)的XPS图谱Fig. 2 XPS spectra of samples after first electrodeposition(a), second electrodeposition (b), Ru3d (c) and O1s (d)

2.2 电化学性能测试

2.2.1 循环伏安测试

循环伏安测试(CV测试)是一种快速定量的测试方法, 可以考察较宽电极范围内电极的反应过程、可逆性、扩散系数以及电极表面的吸/脱附特征, 比较直观地反映电极表面电化学行为。在CV测试中, 可根据CV曲线按下式求出膜电极比容量:

(1)

式中, C(F/m²)为电极比容量, 表示CV曲线所包围的面积, (V)为扫描电压范围, υ (V/s)为扫描速度, S(m²)为有效面积。在CV曲线中则直观表现为曲线所包围的面积越大, 电容量越大。图3为扫描速率为100 mV/s时样品的CV曲线, 可以看出, 3个样品的CV曲线均具有较好的对称性, 说明样品在0.5 mol/L NaCl电解液中氧化还原的可逆性较好, 且无明显的氧化还原峰, 表明样品具有明显的电容特性和较好的法拉第反应特性。随着热处理温度的升高, 样品CV曲线所包围的面积随之增大, 根据公式(1), 计算得出PGR25、PGR65和PGR105的比电容分别为17.5、28.0和28.5 mF/cm²。当热处理温度从25℃升高

到65℃时, PGR65样品的比电容值比PGR25明显提高; 当热处理温度继续升高到105℃时, PGR105样品的比电容小幅提高, 说明在一定温度范围内, 提高样品的热处理温度有助于提高电化学性能。

2.2.2 交流阻抗测试

采用交流阻抗方法测量对样品施加小幅度微扰时发生的电化学响应, 据此研究样品的阻抗以及电极反应机理等, 可以全面评价样品的大电流充放电性能和高功率输出的能力。实验过程中在样品上施加一个5 mV的小幅正弦交流信号, 信号的频率范围为0.1 Hz~ 100 kHz, 测试结果如图4所示。从图4中可看出, 3个样品的交流阻抗谱曲线在高频区均有一段圆弧, 说明有法拉第阻抗存在; 在低频区均为直线, 说明均存在双电层电容, 因此3个样品的电容值均是法拉第效应与双电层效应协同作用的结果。比较高频区圆弧的直径, 可以得到PGR25、PGR65和PGR105样品的转移电阻值(R_ct)分别为9.6、4.2和2.6 Ω , 表明电解质中的粒子在PGR105样品内部迁移更容易, 使得PGR105样品的电极反应更迅速。可以认为随着热处理温度的升高, 膜材料间的孔隙尺寸增大, 为电解质中的粒子在膜电极内部迁移提供更加通畅的通道, 使得电解质进入膜结构孔隙区域的能力得到提高。

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	图3 不同温度处理后RuO₂复合薄膜CV曲线Fig. 3 CV curves of RuO₂composite film after heat-treatment at different temperatures

2.2.3 能量密度与功率密度

图5是电位窗口为1 V, 扫描速度为100 mV/s时, 不同温度热处理后的RuO₂复合薄膜的能量密度与功率密度Ragone曲线。Ragone曲线中能量密度参数表征电极储能多少, 功率密度参数表征电极大电流快速充放电能力, 分别可由公式(2)和(3)计算:

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	图4 不同温度处理后RuO₂复合薄膜的Nyquist图谱Fig. 4 Nyquist plots of RuO₂ composite films after heat- treatment at different temperatures

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	图5 不同温度处理后RuO₂复合薄膜的Ragone曲线图Fig. 5 Ragone plot of RuO₂ composite films after heattreatment at different temperatures

(2)

(3)

其中, 为放电时间。根据公式(2)、(3)计算出PGR25、PGR65和PGR105样品的能量密度分别为0.024、0.039和0.04 Wh/m², 功率密度分别为8.75、14和14.25 W/m²。从图5中可以看出, 当热处理温度从25℃升高到65℃时, PGR65样品的能量密度与功率密度比PGR25样品均有大幅度提高, 当热处理

温度继续升高到105℃时, PGR105样品的能量密度与功率密度增幅较小, 说明在一定温度范围内, 提高处理温度有助于提高膜电极的能量存储及释放性能。

3 结论

采用分步电沉积方法在三维微结构Ni集流体上制备出以PPy/GO薄膜为基底的RuO₂复合膜电极。结果表明: 经两次25、65和105℃热处理后的PGR25、PGR65和PGR105样品比电容依次为17.5、28.0和28.5 mF/cm², 能量密度依次为0.024、0.039和0.04 Wh/m², 功率密度依次为8.75、14和14.25 W/m²。这说明在一定温度范围内, 对分步电沉积法制备的RuO₂复合膜电极进行热处理, 有助于提高膜电极的能量存储及释放性能。该方法在成功避免因RuO₂

沉积电位过高而无法直接在三维微结构金属集流体表面沉积问题, 还降低了贵金属Ru使用量, 因此在MEMS超级电容器电极材料制备方面有着广泛的应用前景。

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[1]	YULIA M, ARTEM U, ALEXANDER S, et al. Nanoporous carbon-based electrode materials for supercapacitors. Solid State Ionics, 2013, 251(11): 59-61. [本文引用:1] [JCR: 2.046]
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[3]	MAJID B, WANG C L. Micro-supercapacitors based on three dimensional interdigital polypyrrole/C-MEMS. Electrochimica Acta, 2011, 56(10): 9508-9514. [本文引用:1] [JCR: 3.777]
[4]	SAADON S, SIDEK O. A review of vibration-based MEMS piezoelectric energy harvesters. Energy Conversion and Management, 2011, 52(1): 500-504. [本文引用:1] [JCR: 2.775]
[5]	BEIDAGHI M, WANG C L. On-chip Micro-power: Three Di-mensional Structures for Micro-batteries and Micro-supercapacitors. Proceedings of the SPIE-The International Society for Optical Engineering, Orland o, 2010, 371(24): 7679-7691. [本文引用:1]
[6]	CHEAH S K, PERRE E, ROOTH M, et al. Self-supported three-dimensional nanoelectrodes for microbattery applications. Nano Letters, 2009, 9(9): 3230-3233. [本文引用:1] [JCR: 13.025]
[7]	ZHU P, HAN G Y. Performance of MEMS microcapacitor based on polypyrole/graphene oxide electrodes. Journal of Functional Materials, 2013, 44(19): 2768-2772. [本文引用:1] [CJCR: 0.588]
[8]	DEEPAK P D, GIRISH S. G, RUDOLF H, et al. Solution-based binder-free synthetic approach of RuO₂ thin films for all solid state supercapacitors. Electrochimica Acta, 2013, 103(7): 103-109. [本文引用:1] [JCR: 3.777]
[9]	SHOYEBMOHAMAD F, SHAIKH J, YEON L, et al. Electrochemical supercapacitors of electrodeposited PANIH-RuO₂ hybrid nanostructure. Current Applied Physics, 2013, 13(4): 758-761. [本文引用:1] [JCR: 1.814]
[10]	JIN Y, CHEN H Y, CHEN M H, et al. Carbon nanotubepolyaniline grapheme composite paper and its electrochemical capacitance behaviors. Acta Physico-Chimica Sinica, 2012, 28(3): 609-614. [本文引用:1] [JCR: 0.869] [CJCR: 1.044]
[11]	LI B S, QI H X, ZHAI W T, et al. Electrosynthsis of large polypyrrole films by multi-potential steps method. Science China Technology Science, 2011, 54(7): 1697-1702. [本文引用:1]
[12]	WANG X Y, HENG L P, YANG N L, et al. Preparation of polypyrrole/polyvinylalcohol (PPy/PVA) composite foam electrode material. Chinese Chemical Letters, 2010, 21(7): 884-887. [本文引用:1] [JCR: 1.21] [CJCR: 0.3729]
[13]	ZHANG Q W, ZHOU X, YANG H S. Carbon foam materials prepared from polyacryonitrile and their application in electrochemical capacitors. Acta Polymerica Sinica, 2003, 12(5): 749-753. [本文引用:1] [JCR: 0.677] [CJCR: 0.963]
[14]	LIU Y F, HU Z H, REN L W. High-performance activated carbons for use in the electrodes of electric double-layer capacitors. New Carbon Materials, 2007, 24(4): 354-360. [本文引用:1] [JCR: 0.981] [CJCR: 1.397]
[15]	LU Y, YUAN J, HU Y D, et al. Preparation and performances of RuO₂/CuO composite electrode materials. Journal of Functional Materials, 2013, 44(19): 2836-2839. [本文引用:1] [CJCR: 0.588]
[16]	SELLAM, HASHMI S A. High rate performance of flexible pseudocapacitors fabricated using ionic-liquid-based proton conducting polymer electrolyte with poly (3, 4-ethylenedioxythiophene): poly (styrene sulfonate) and its hydrous ruthenium oxide composite electrodes. ACS Applied Materials & Interfaces, 2013, 5(9): 3875-3883. [本文引用:1]
[17]	WANG J, XU Y L, MA J H, et al. Supercapacitor electrode materials of nanostructured hydrous ruthenium oxide deposited by cyclic voltammetry method. Rare Metal Materials and Engineering, 2012, 41(8): 1467-1471. [本文引用:1] [JCR: 0.16] [CJCR: 0.827]
[18]	WEN C M, WEN Z Y, YOU Z, et al. Preparation and characterization of manganese oxide microelectrodes for microelectromechanical system supercapacitors. Journal of Nanoengineering and Nanosystems, 2014, 228(2): 77-81. [本文引用:1]
[19]	HUANG X Q, GAN W P, YANG J, et al. Preparation and characteristic of Co-doped (RuO₂/Co₃O₄)·nH₂O composite film electrode. Materials Science and Engineering of Powder Metallurgy, 2013, 18(1): 107-112. [本文引用:1] [CJCR: 0.602]
[20]	HU A Z, ZHANG Y J, NU A L, et al. Synthesis and electrochemical characterization of RuO₂·xH₂O/graphite nano sheet composite array electrodes for supercapacitors. Acta Physico-Chimica Sinica, 2013, 29(2): 305-310. [本文引用:3]
[21]	WU Z S, WANG D W, REN J, et al. Anchoring hydrous RuO₂ on grapheme sheets for high-performance electrochemical capacitors. Advanced Functional Materials, 2010, 20(1): 3595-3602. [本文引用:1] [JCR: 9.765]
[22]	CHASTAIN J. Hand book of X-ray Photoelectron Spectroscopy. Perkin Elmer Corp. , Minnesota, 1992. [本文引用:1]

2013

2.046

0.0

Solid State Ionics. 2013, 251(11):59-61

Nanoporous carbon-based electrode materials for supercapacitors.

YULIA M , ARTEM U , ALEXANDER S

New nanoporous carbon materials were synthesized from organic precursors, and their electrochemical properties were investigated by cyclic voltammetry in acid and alkali electrolytes (6 M KOH or 1 M H 2 SO 4 ). A correlation between specific capacitance and specific surface area was observed. Because of higher specific capacitance values (130–335 F/g), the carbon materials under study may be regarded as promising materials for electrochemical supercapacitors.

... 相关研究工作主要分为两类^{[1,2,3,4,5,6,7]}: (1)最大程度提高膜材料的比表面积, 开发每平方厘米或每克能实现的最大双电层电容 ...

2013

0.981

1.397

... 相关研究工作主要分为两类^{[1,2,3,4,5,6,7]}: (1)最大程度提高膜材料的比表面积, 开发每平方厘米或每克能实现的最大双电层电容 ...

2011

3.777

0.0

Electrochimica Acta. 2011, 56(10):9508-9514

Micro-supercapacitors based on three dimensional interdigital polypyrrole/C-MEMS.

MAJID B , WANG C L.

Symmetric micro-supercapacitors with three dimensional (3D) interdigital electrode structures have been designed and fabricated through Carbon-microelectrochemical system (C-MEMS) technology. The micro-supercapacitor consists of a 3D C-MEMS structure which serves as a high effective surface area current collector and conformal polypyrrole (PPy) films deposited on the carbon structures as electroactive materials. The electrochemical performance of single electrodes and symmetric micro-supercapacitor cells were evaluated by cyclic voltammetry (CV) at different scan rates and galvanostatic charge/discharge tests. The effect of the 3D electrode structure on the performance of the micro-supercapacitor was studied. Single PPy/C-MEMS electrodes presented a specific capacitance of 162.07 ± 12.40 mF cm −2 and a specific power of 1.62 ± 0.12 mW cm −2 at 20 mV s −1 scan rate. The symmetric micro-supercapacitor cells exhibited an average specific capacitance of 78.35 ± 5.67 mF cm −2 and a specific power of 0.63 ± 0.04 mW cm −2 at 20 mV s −1 scan rate, demonstrating that 3D micro-supercapacitors are promising for applications that require high power in a limited footprint area of the device.

... 相关研究工作主要分为两类^{[1,2,3,4,5,6,7]}: (1)最大程度提高膜材料的比表面积, 开发每平方厘米或每克能实现的最大双电层电容 ...

2011

2.775

0.0

Energy Conversion and Management. 2011, 52(1):500-504

A review of vibration-based MEMS piezoelectric energy harvesters.

SAADON S , SIDEK O.

The simplicity associated with the piezoelectric micro-generators makes it very attractive for MEMS applications, especially for remote systems. In this paper we reviewed the work carried out by researchers during the last three years. The improvements in experimental results obtained in the vibration-based MEMS piezoelectric energy harvesters show very good scope for MEMS piezoelectric harvesters in the field of power MEMS in the near future.

... 相关研究工作主要分为两类^{[1,2,3,4,5,6,7]}: (1)最大程度提高膜材料的比表面积, 开发每平方厘米或每克能实现的最大双电层电容 ...

2010

0.0

... 相关研究工作主要分为两类^{[1,2,3,4,5,6,7]}: (1)最大程度提高膜材料的比表面积, 开发每平方厘米或每克能实现的最大双电层电容 ...

2009

13.025

0.0

Nano Letters. 2009, 9(9):3230-3233

Self-supported three-dimensional nanoelectrodes for microbattery applications.

CHEAH S K , PERRE E , ROOTH M

A nanostructured three-dimensional (3D) microbattery has been produced and cycled in a Li-ion battery. It consists of a current collector of aluminum nanorods, a uniform layer of 17 nm TiO 2 covering the nanorods made using ALD, an electrolyte and metallic lithium counter electrode. The battery is electrochemically cycled more than 50 times. The increase in total capacity is 10 times when using a 3D architechture compared to a 2D system for the same footprint area.

... 相关研究工作主要分为两类^{[1,2,3,4,5,6,7]}: (1)最大程度提高膜材料的比表面积, 开发每平方厘米或每克能实现的最大双电层电容 ...

2013

0.0

0.588

... 相关研究工作主要分为两类^{[1,2,3,4,5,6,7]}: (1)最大程度提高膜材料的比表面积, 开发每平方厘米或每克能实现的最大双电层电容 ...

2013

3.777

0.0

Electrochimica Acta. 2013, 103(7):103-109

G, RUDOLF H, et al. Solution-based binder-free synthetic approach of RuO₂ thin films for all solid state supercapacitors.

DEEPAK P D , GIRISH S.

In this rising field of portable electronics, all solid state thin film supercapacitors (ASSTFSs) have received tremendous courtesies due to their flexibility and high safety, which are considered as competitive candidates for energy power sources in flexible electronics. In present investigation, we demonstrate the first successful application of pseudocapacitive RuO 2 in ASSTFS, exhibiting high capacitance, remarkable high-rate capability and long-term cycling stability. Nanocrystalline RuO 2 thin films are developed on mesh like stainless steel substrate by facile chemical bath deposition (CBD) method at three different deposition temperatures. ASSTFSs were fabricated by simple process using two slightly separated RuO 2 thin films well solidified in the H 2 SO 4 –polyvinyl alcohol gel electrolyte. Electrochemical studies of ASSTFS device was characterized by cyclic voltammetry, charge–discharge and impedance techniques. The highest specific capacitance of 234, 203 and 167 F g −1 for three RuO 2 nanostructures was obtained. Further the device shows good stability after 1000 cycles. The non-ideal behavior of the supercapacitor was analyzed by impedance analysis. Additionally, the all-solid-state nature combined with superior electrochemical performance makes RuO 2 -based device an excellent candidate for power sources in portable electronics.

... 实际的孔隙尺寸分布极大地取决于功能材料的来源及其预处理, 如: 常规膜材料设计一般选用碳系材料(如CNT)、氧化还原氧化物(如RuO₂), 或者活性聚合物(如PPy)等功能材料来实现^[8,9,10,11] ...

2013

1.814

0.0

Current Applied Physics. 2013, 13(4):758-761

Electrochemical supercapacitors of electrodeposited PANIH-RuO₂ hybrid nanostructure.

SHOYEBMOHAMAD F , SHAIKH J , YEON L

Electrodeposited mixed nanostructures composed of conducting polyaniline (PANI) and hydrous ruthenium oxide (H-RuO 2 ) referred as a hybrid nanostructure was synthesized. The surface morphology was investigated from the field-emission scanning electron microscopy digital photoimages. Fibrous network of PANI and spheres of H-RuO 2 were obtained. PANI embedded H-RuO 2 was confirmed from the Raman spectroscopy analysis. Cyclic-voltammetry, used to characterize the electrochemical capacitive properties of hybrid PANI/H-RuO 2 (RP 30) nanostructure, showed a specific capacitance as high as 322 F/g in 0.5 M H 2 SO 4 electrolyte. The electrochemical impedance spectroscopy measurement revealed the low equivalent series resistance.

2012

0.869

1.044

2011

0.0

Science China Technology Science. 2011, 54(7):1697-1702

Electrosynthsis of large polypyrrole films by multi-potential steps method.

LI B S , QI H X , ZHAI W T

Polypyrrole (PPy) films were prepared by multi-potential steps polymerization in an aqueous pyrrole solution, with lithium perchlorate and oxalic acid as supporting electrolytes. Morphology and structure of PPy films were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Electrochemical behaviors of PPy films were studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results show that multi-potential steps polymerization improves the conductivity of PPy films and large polymer films can be peeled off easily from the electrode without cracking. Lithium perchlorate and oxalic acid provide appropriate dopants for PPy polymerization. It was observed that the polymerization time and the current density have a crucial influence on the surface morphology of PPy films. Smooth and compact PPy films could be generated under long polymerization time and low current density. Multi-potential steps polymerization decreases the occurrence of peroxidation, which improves the conductivity of PPy films. The parameters for multi-potential steps polymerization have been optimized.

2010

1.21

0.3729

Chinese Chemical Letters. 2010, 21(7):884-887

Preparation of polypyrrole/polyvinylalcohol (PPy/PVA) composite foam electrode material.

WANG X Y , HENG L P , YANG N L

Polypyrrole/polyvinylalcohol (PPy/PVA) foam was prepared by direct foam polymerization in water and then it was coated on the indium-tin oxide transparent conductive glass (ITO) to form conventional three-electrode cell. FTIR and UV–vis spectra were adopted to characterize the molecular structure and the absorption spectra of foam material, respectively. The porous structure of PPy/PVA foams and their photoelectric conversion behaviors were studied. The dimension of the pores is bigger than 100 μm in diameter. Compared with the smooth film, the V oc and I sc of the foam film enhanced by 1.58-fold and 5.59-fold, respectively.

... 功能材料预处理一般是对合成聚合物(如丙烯腈C₃H₃N)进行碳化, 或者对天然有机物(如椰子壳)进行碳化^[12,13,14] ...

2003

0.677

0.963

... 功能材料预处理一般是对合成聚合物(如丙烯腈C₃H₃N)进行碳化, 或者对天然有机物(如椰子壳)进行碳化^[12,13,14] ...

2007

0.981

1.397

... 功能材料预处理一般是对合成聚合物(如丙烯腈C₃H₃N)进行碳化, 或者对天然有机物(如椰子壳)进行碳化^[12,13,14] ...

2013

0.0

0.588

... 目前, MEMS超级电容器膜电极材料主要包括: 碳系列材料、金属氧化物和导电聚合物^[15] ...

2013

0.0

... 100 S/cm)和良好的循环稳定性^[16], 适合用于超级电容器 ...

2012

0.16

0.827

... 然而, 采用电沉积法在微米级的集流体三维结构上沉积RuO₂却有两个难点: (1)由于RuO₂沉积电位较高, 难以在金属集流体表面直接沉积^[17,18] ...

2014

0.0

... 然而, 采用电沉积法在微米级的集流体三维结构上沉积RuO₂却有两个难点: (1)由于RuO₂沉积电位较高, 难以在金属集流体表面直接沉积^[17,18] ...

2013

0.0

0.602

... 通常的解决方法是在RuO₂中掺杂石墨等材料来减少RuO₂用量, 从而提高Ru的利用率和膜材料比容量^[19,20] ...

2013

0.0

... 通常的解决方法是在RuO₂中掺杂石墨等材料来减少RuO₂用量, 从而提高Ru的利用率和膜材料比容量^[19,20] ...

... 如, Hu等^[20]通过电化学剥离法先在石墨棒表面构筑有序的二维石墨纳米片阵列, 再采用阴极还原法在阵列表面均匀包覆一层RuO₂薄膜形成的复合膜电极效果最佳, 比容量高达4226 F/m² ...

... 因此, Hu等^[20]的制备方法不适用于MEMS超级电容器 ...

2010

9.765

0.0

Advanced Functional Materials. 2010, 20(1):3595-3602

Anchoring hydrous RuO₂ on grapheme sheets for high-performance electrochemical capacitors.

WU Z S , WANG D W , REN J

Hydrous ruthenium oxide (RuO 2 )/graphene sheet composites (ROGSCs) with different loadings of Ru are prepared by combining sol–gel and low-temperature annealing processes. The graphene sheets (GSs) are well-separated by fine RuO 2 particles (5–20 nm) and, simultaneously, the RuO 2 particles are anchored by the richly oxygen-containing functional groups of reduced, chemically exfoliated GSs onto their surface. Benefits from the combined advantages of GSs and RuO 2 in such a unique structure are that the ROGSC-based supercapacitors exhibit high specific capacitance (∼570 F g −1 for 38.3 wt% Ru loading), enhanced rate capability, excellent electrochemical stability (∼97.9% retention after 1000 cycles), and high energy density (20.1 Wh kg −1 ) at low operation rate (100 mA g −1 ) or high power density (10000 W kg −1 ) at a reasonable energy density (4.3 Wh kg −1 ). Interestingly, the total specific capacitance of ROGSCs is higher than the sum of specific capacitances of pure GSs and pure RuO 2 in their relative ratios, which is indicative of a positive synergistic effect of GSs and RuO 2 on the improvement of electrochemical performance. These findings demonstrate the importance and great potential of graphene-based composites in the development of high-performance energy-storage systems.

... 0 eV)^[21], 可以认为电沉积法获得的是由多氧化态Ru组成的混合羟基氧化物 ...

1992

0.0

... 5 eV处的强峰对应于Ru-OH键^[22] ...