高等学校化学学报

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Cu/Cu2+沉积型电极在流动酸性电解液中的电化学性能

潘君丽1,2, 文越华2, 程杰2, 曹高萍2, 杨裕生1,2   

  1. 1. 北京化工大学理学院, 北京 100029;
    2. 北京防化研究院, 北京 100191
  • 收稿日期:2011-09-05 发布日期:2012-02-16
  • 通讯作者: 文越华, 女, 博士, 副研究员, 主要从事化学电源研究. E-mail:wen_yuehua@126.com
  • 基金资助:

    国家"九七三"计划项目(批准号: 2010CB227201)和国家自然科学基金(批准号: 50804050)资助.

Electrochemical Performance of Cu/Cu2+ Electrodes in Flow Concentrated Acidic Electrolytes

PAN Jun-Li1,2, WEN Yue-Hua2, CHENG Jie2, CAO Gao-Ping2, YANG Yu-Sheng1,2   

  1. 1. College of Science, Beijing University of Chemical Technology, Beijing 100029, China;
    2. Research Institute of Chemical Defence, Beijing 100191, China
  • Received:2011-09-05 Published:2012-02-16

摘要:

在流动的高浓度硫酸铜酸性溶液中, 研究了H2SO4浓度、 温度和CuSO4浓度对Cu/Cu2+沉积型电极在石墨基体上电化学性能的影响. 结果表明, 沉积型铜电极反应受控于阴极沉积过程, 室温下动力学过程较慢, 但铜沉积致密, 不易形成枝晶和海绵状铜. 适当提高H2SO4和CuSO4浓度及反应温度可降低铜沉积的极化, 改善其动力学特征; 但Cu离子的溶解度受限于H2SO4浓度, CuSO4浓度提升空间有限. 优化电解液组成为2.5 mol/L H2SO4+0.7 mol/L CuSO4, 反应温度45 ℃. 在此条件下, 铜在石墨基体上沉积/溶解的交换电流密度提高1个数量级, 具有良好的动力学特征, 单电极充放电电压差降低近50%, 能量效率超过80%.

关键词: 流动酸性电解液, 铜电沉积, 石墨基体, 电化学性能

Abstract:

In flow concentrated acidic electrolytes of cupric sulfate, the effects of concentration of H2SO4, CuSO4 and temperature on the electrochemical performance of Cu/Cu2+ electrodes on the graphite substrate were investigated by electrochemical measurements combined with scanning electron microscope(SEM) techniques. The results show that the electrode reaction of deposition-type copper electrodes is controlled by the cathodic process. The kinetics is relatively slow at room temperature. But, the copper deposits are compact. The dendritic and spongy growth are not easy to take place. The polarization of copper deposition can be lowered by increasing the concentration of H2SO4, CuSO4 and temperature to some extent, improving the kinetic characteristics of copper deposition. But, an increase in the solubility of CuSO4 is dependent on the concentration of H2SO4. The optimized composition of the electrolyte is 2.5 mol/L H2SO4+0.7 mol/L CuSO4. The reaction temperature is 45 ℃. Under the optimized condition, the exchange current density of copper deposition/dissolution on the graphite substrate at 45 ℃ is enhanced by one order of magnitude, indicative of favorable kinetics characteristics. As a result, the charge-discharge voltage difference of the deposition-type copper electrode is decreased by nearly 50% and the energy efficiency is beyond 80%. It is expected that the performance of the Cu-PbO2 acidic single flow battery would be improved further.

Key words: Flow acidic electrolyte, Copper electro-deposition, Graphite substrate, Electrochemical performance

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