Porous Ge based Electric Double Layer Capacitors with High Compatibility for Low Threshold Voltage Diode Rectifiers

14th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications

物理学;能源学

Sekiguchi, A.^1 ; Hara, M.^1 ; Oguchi, H.^1 ; Kuwano, H.^1

Department of Nano-Mechanics, Tohoku University, 6-6-01, Aoba, Sendai, Aramaki, Aza- Aoba

980-8579, Japan^1

关键词: AC impedance measurement;    Acid solutions;    Dopant concentrations;    Electric double-layer capacitor (EDLC);    High surface area;    Low threshold voltage;    Surface etching;    Surface stability;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/557/1/012105/pdf
DOI  :  10.1088/1742-6596/557/1/012105

来源: IOP

【 摘 要 】

The final goal of this study is to develop all-Ge-based energy harvesting modules consisting of mechanical generators, rectifiers, capacitors and power managing digital circuits. To make basis for the development of modules, we focused on development of the Ge electrodes for electric double layer capacitors (EDLC). Firstly, to establish a method to make high surface area Ge electrodes, we studied surface etching of the Ge(100) substrates in the acid solution. We found that the substrates with higher dopant concentration forms smaller size micro-pores with higher area density that leads to higher surface area. Secondly we studied stability of Ge in the ionic liquid (IL) electrolyte by ac impedance measurements. The impedance plots verified that Ge is reactive in IL electrolyte, thus not appropriate for electrodes without surface modification. Finally we oxidized Ge surface and tested the stability again. The impedance plot of the surface- oxidized Ge showed little reaction, proving that we succeeded to improve the surface stability.