Han Zhifei, Qi Zhengpan, Wei Qiang, Deng Qibo, Wang Ke
Tianjin Key Laboratory of Advanced Functional Porous Materials, Institute for New Energy Materials & Low-Carbon Technologies, School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384, China.
Research Institute for Structure Technology of Advanced Equipment, School of Mechanical Engineering, Hebei University of Technology, Tianjin 300401, China.
Nanomaterials (Basel). 2020 Oct 18;10(10):2056. doi: 10.3390/nano10102056.
This study investigated the electrochemical actuation behavior of nanoporous material during the capacitive process. The length change of nanoporous gold (npg) was in situ investigated in a liquid environment using the dilatometry technique. The mechanical effect of MnO layers was introduced in this work to improve the actuation characteristics of the npg samples. Our work found that the actuation behavior of npg sample could be significantly modulated with a covering of MnO layers. The electrochemical actuation amplitude was efficiently improved and strongly dependent on the thickness of MnO layers covered. Aside from the amplitude, the phase relation between the length change and the electrode potential was inverted when covering the MnO layer on the npg samples. This means the expansion of the npg samples and the contraction of samples covered with the MnO layer when electrochemical potential sweeps positively. A simple finite element model was built up to understand the effect of the MnO layer. The agreement between the simulation result and the experimental data indicates that the sign-inverted actuation-potential response of nanoporous gold contributes to the mechanical effect of MnO. It is believed that our work could offer a deep understanding on the effect of the MnO layer on the electrochemical actuation and then provide a useful strategy to modulate the actuation performance of nanoporous metal materials.
本研究考察了纳米多孔材料在电容过程中的电化学驱动行为。采用膨胀测量技术在液体环境中原位研究了纳米多孔金（npg）的长度变化。在这项工作中引入了MnO层的力学效应，以改善npg样品的驱动特性。我们的工作发现，MnO层的覆盖可以显著调节npg样品的驱动行为。电化学驱动幅度得到有效提高，且强烈依赖于所覆盖MnO层的厚度。除了幅度之外，在npg样品上覆盖MnO层时，长度变化与电极电位之间的相位关系发生了反转。这意味着当电化学电位正向扫描时，npg样品膨胀，而覆盖有MnO层的样品收缩。建立了一个简单的有限元模型来理解MnO层的作用。模拟结果与实验数据之间的一致性表明，纳米多孔金的驱动电位响应符号反转是由MnO的力学效应导致的。相信我们的工作能够深入理解MnO层对电化学驱动的影响，进而提供一种调节纳米多孔金属材料驱动性能的有用策略。
