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电化学超级电容器电极材料的研究

Research on the Materials for Electrochemical Supercapacitors

【作者】 刘彦芳

【导师】 张宝宏;

【作者基本信息】 哈尔滨工程大学 , 应用化学, 2004, 硕士

【摘要】 电化学超级电容器是一种介于蓄电池和常规电容器之间的新型储能设备及器件,它具有比常规电容器更大的比能量,比蓄电池更大的比功率和循环使用寿命。利用超级电容器和电池组成混合动力系统,能够很好的满足电动汽车启动、加速等高功率密度输出场合的需要。它可以应用于很多领域,如:混合电动汽车、燃料电池、移动电话、微机等。根据储能原理,超级电容器可以分为双电层电容和法拉第准电容,电极材料主要包括碳材料、金属氧化物和导电聚合物。 本文主要采用了循环伏安、恒电流充放电、交流阻抗以及透射电子显微镜等测试手段对超级电容器的电极活性物质材料进行了研究。对于碳材料,本文主要对活化方法进行了研究,结果发现用硝酸活化处理后的活性炭在浓度为7mol/L的氢氧化钾溶液中具有良好的电容性能。并且进行了硝酸的浓度实验和氨水活化时间的实验,发现容量随硝酸浓度的增加而增加,随氨水活化时间的增加而减少。由于碳基电容器正极容量远小于负极容量,所以本文主要致力于开发新的正极材料与作为负极的碳电极组成混合电容器。用固相合成法制备Ag2O作为超级电容器材料,通过循环伏安与恒流充放电等测试手段对Ag2O电极及与作为负极的活性炭电极组成的电容进行分析。结果表明,在7mol·L-1KOH电解液中,Ag2O电极在0.15~0.35V(vs.Hg/HgO)的电压范围内表现出了法拉第电容特性。在不同电流密度下,电极比容量达427.3~554.9 F·g-1,Ag2O/活性炭单体电容器比电容为42.5~61.65F·g-1。同时还对正极中Ag2O的含量及导电剂对Ag2O/活性炭单体电容器性能的影响进行了研究。用固相合成法制备了α-PbO、β-PbO、PbO2和MnO2。用MnO2作为超级电容器正极电极材料,并通过在正极活性物质中加入不同的铅的氧化物探讨其对正极容量的影响。实验表明添加β-PbO的MnO2电极在7mol·L-1KOH溶液中在-0.3~0.4V(vs Hg/HgO)的电压范围内有良好的法拉第电容特性。添加2%β-PbO的MnO2电极比容量达165.7~260F·g-1,比无添加剂的MnO2电极的比容量高出62.5%,从实验数据可见,添加的配比对电化学性能的影响较大,添加量为2%时,电极具有良好的电容性能。从2000哈尔滨工程大学硕士学位论文次的循环性能看,在电流密度为somA·cm.2时,添加p一Pbo的MnOZ电极仍具有较好的循环性,容量衰减不到10%.同时,我们用活性炭做负极,二氧化锰做正极成功制备出了千法级混合超级电容器,容量可达20()0F,比能量可达SWh飞g,循环寿命可达2万次.关键词:电化学超级电容器;活性炭;氧化银;氧化铅;二氧化锰犷

【Abstract】 Electrochemical supercapacitor is a new energy storage equipment and component between batteries and electrostatic capacitors, which has higher energy density than that of electrostatic capacitor and higher power density than that of batteries. When working with batteries, they can meet the high power out-put need of electric vehicles when starting-up or accelerating. It can also be applied into many fieids such as hybrid electric vehicle ,fuel cell mobile telephone and microcomputer. According to the principle of energy-storage there are two types of capacitors: electric double-layer capacitor and faradaic pseudocapacitor. Electrode material mainly includes carbon material, metal oxide and conducting polymer.A series of experiments were conducred to research on electrode material with the aids of the measure methods such as cyclic voltammetric measurements (CV), constant charge/discharge measurements, impedance spectrum, transmission electronic microscope measurements(TEM), and so on. As for carbon material, its activation in nitrate acid; In addition, we also studied the effect on capacitance of nitrate acid concentration and activation time in ammonia. The conclusion were obtained that electrode capacitance enhance with the increase of nitrate acid concentration, and decreased with the activation time in ammonia. The paper also found that the positive carbon electrode was much smaller than that of negative one, so it urged to develop new positive material to make up hybrid capacitor. Abstract The Ag2O was synthesized by solid-phase reaction as electrode material for electrochemical supercapacitor that was tested by cyclic voltammetry(CV) and constant charge-discharge curves. The results of experiment show that Ag2O electrode has good performance of faradic pseudocapacitance in 7molL-1’KOH between 0.15 and 0.35V(vs Hg/HgO). The electrode can provide a specific capacitance of 427.3 to 554.9 Fg-1 and the Ag2O/active carbon electrodes can provide a specific capacitance of 42.5 to 61.65 F-g-1 at different current densities. The effect of Ag2O content in the cathode and conductive substance on Ag2O/active carbon electrodes performance was also studied. The -PbO, -PbO, PbO2 and MnO2 were synthesized by solid-phase reaction. We use MnO2as the positive electrode material and add different lead oxide to the positive material.The results of experiment show that MnO2 electrode of adding P -PbO has good performance of faradic pseudocapacitance in TmolL"1 KOH between -0.3 and 0.4V(vs Hg/HgO). MnO2 electrode of adding 2% 3 -PbO can provide a specific capacitance of 165.7 to 260Fg"’ that inhance by 65% than that of no additive. It appeared that the ratio of P -PbO in samples had greater effect on the electrochemical capacity. The better discharge capacity could be obtained when the ratio of P -PbO was 2%. After 2000 cycles of constant charge-discharge the electrode was stable and the capacitance reduces no more than 10% at current density of 50mAcm"2. Successfully we made kilifarads hybrid capacitor ,the anode is active carbon electrode and the cathode is MnO2 electrode.Its capacitance is 2000F. Its specific energy is 5Wh/kg. Its cyclic life was over 20000 cycles.

  • 【分类号】TM53
  • 【被引频次】7
  • 【下载频次】1210
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