Silicon-based Micro Fuel Cell Membrane Electrode Assembly for Energy Supply of Portable Electronic Devices and High Throughput Material Characterization
Portable electronic devices like smartphones, tablet PC’s or wearables have become an essential part of everyday life. Continuous integration of more features like GPS or Bluetooth has led to significant technical improvements and convenience, but also to increased energy requirements. The last part of the thesis investigates the potential of silicon-based micro membrane electrode assemblies to be used in high throughput material research. An experimental setup was designed, manufactured and assembled which allows initiating a fuel cell reaction under defined ambient conditions on a number of different electrode configurations.
However, the development of new battery technologies with higher energy density is lacking behind which results in lower usage duration between single recharge cycles. Hence, the identification of alternative technologies is crucial for future success of portable, connected devices, especially in the field of the internet of things.
The development of innovative micro fuel cells may be an interesting approach to reach the goal of high energy capacity with minimal volumetric requirements. For this, it is mandatory to find solutions for miniaturization of the fuel cell. In this thesis, essential concepts for fabrication of silicon-based micro electrode membrane assemblies are developed with a focus on applicability of mass fabrication.
On the one hand, this includes the design of a concept to manufacture ultra-thin, microstructured membranes which serve as mechanical basis for the membrane electrode assemblies as well as development of a process to integrate a proton conducting ionomer into the microstructure of the membrane. On the other hand, different electrode configurations were realized and characterized in detail. This includes the use of established methods like measurement of polarization curves and the use of electrochemical impedance spectroscopy, but also the application of specialized characterization methods, namely electrochemical atomic force microscopy which makes it possible to validate the proton conductivity of single micro channels of the proton conducting membrane.
The electrodes are characterized regarding their heat of reaction with the help of emissivity corrected infrared spectroscopy. Because of the utilization of semiconductor processes, it is possible to manufacture a large quantity of varying electrode configurations. At the same time, the ultra-thin design of the micro membrane electrode assemblies makes it possible to allocate the origin of the heat of reaction precisely. This allows to evaluate different electrodes in parallel and to draw conclusion regarding the effectivity of the fuel cell reaction.
The last part of the thesis investigates the potential of silicon-based micro membrane electrode assemblies to be used in high throughput material research. An experimental setup was designed, manufactured and assembled which allows initiating a fuel cell reaction under defined ambient conditions on a number of different electrode configurations.