Silicon-based fuel cell

Z. Y. Xiao, G. Z. Yan, C. H. Feng, P. G. H. Ghan, and I. M. Hsing. A silicon-based fuel cell micropower system using a microfabrication technique. Journal of Micromechanics and Microengineering 16 (2006) 2014 2020. 

Hybrid Versions of Silicon-Based Fuel Cells... 

Betthauer et al. (2011) developed a novel integrated silicon chip fuel cell type of accumulator that is based on nonprecious metals only. The key component of this accumulator is a low-cost AB2-type hydrogen storage electrode. The accumulator has an OCV of 0.81 V and develops a maximum power density of 0.66 mW/cm —comparable or even superior to former precious metal-based cells. 

Lu GQ, Wang CY, Yen TJ, Zhang X. 2004. Development and characterization of a silicon-based micro direct methanol fuel cell. Electrochim Acta 49 821-828. 

During the course of the last century, it was realized that many properties of solids are controlled not so much by the chemical composition or the chemical bonds linking the constituent atoms in the crystal but by faults or defects in the structure. Over the course of time the subject has, if anything, increased in importance. Indeed, there is no aspect of the physics and chemistry of solids that is not decisively influenced by the defects that occur in the material under consideration. The whole of the modem silicon-based computer industry is founded upon the introduction of precise amounts of specific impurities into extremely pure crystals. Solid-state lasers function because of the activity of impurity atoms. Battery science, solid oxide fuel cells, hydrogen storage, displays, all rest upon an understanding of defects in the solid matrix. 

Besides silicon, other materials have also been used in micro fuel cells. Cha et al. [79] made micro-FF channels on SU8 sheets—a photosensitive polymer that is flexible, easy to fabricate, thin, and cheaper than silicon wafers. On top of fhe flow channels, for both the anode and cathode, a paste of carbon black and PTFE is deposited in order to form the actual diffusion layers of the fuel cell. Mifrovski, Elliott, and Nuzzo [80] used a gas-permeable elastomer, such as poly(dimethylsiloxane) (PDMS), as a diffusion layer (with platinum electrodes embedded in it) for liquid-electrolyte-based micro-PEM fuel cells. 

S. Aravamudhan, A. R. A. Rahman, and S. Bhansali. Porous silicon-based orientation independent, self-priming micro direct ethanol fuel cell. Sensors Actuators A 123-124 (2005) 497-504. 

J. Yeom, G. Z. Mozsgai, B. R. Flachsbart, et al. Microfabrication and characterization of a silicon-based millimeter scale, PEM fuel cell operating with hydrogen, methanol, or formic acid. Sensors Actuators B 107 (2005) 882-891. 

Semiconductor fabrication techniques permit the feature size of Si-based devices to reach into the deep submicron regime [i]. Additionally, Si can be anodized electrochemically or chemically (e.g., in an HF-containing electrolyte) to produce a sponge-like porous layer of silicon, with pore dimensions that range from several microns in width to only a few nanometers [ii]. These properties of Si make it a useful substrate for fabricating sensor platforms, photonic devices and fuel cell electrodes [iii]. 

The development of MEMS technology during the 80s induced a strong research effort focused on fluid and heat flow studies in microchannels. Since then, various silicon-based systems such as microbiochips, MOEMS, etc... have contributed to reinforce this trend and a lot of experimental results were published. In parallel to these studies, very compact heat exchangers for air conditioning purposes were developed and have lead to research programs on minichannels. In the same manner, the possible use of such minichannels in other systems such as reformers, fuel cells,... has also produced considerable interest in this field. 

The method discussed shows the availability of platinum coats as catalytic layers for electrodes of micro fuel cells based on porous silicon. The calculated specific surface area confirms the efficiency of the coats obtained. 

Sealing in fuel cell is required to separate gases entering into the cell. The materials for sealing should withstand the acidic environment of electrolyte and be durable for long-term operation. Silicone rubber based materials are widely employed because of their elasticity and excellent heat resistance. Silicone based materials, however, are degraded during the operation due... 

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