Chunguang Suo

Novel modification of Nafion®117 for a MEMS-based micro direct methanol fuel cell (μDMFC)

Nowadays the micro direct methanol fuel cell (μDMFC) has received much attention as a leading candidate for portable power of the future. This paper presents a novel modification method of the commercial proton exchange membrane Nafion®117 to produce an improved polymer electrolyte membrane for the μDMFC. The method involves using γ-ray radiation and electroless palladium deposition on a Nafion®117 membrane. Specific scopes of the γ-ray radiation dose may cause membrane crosslinking, thus reduce the membrane swelling ratio and decrease methanol crossover. The electroless palladium deposition on the γ-ray radiation modified Nafion®117 further decreases methanol crossover. The modified membrane was characterized using a scanning electron microscope (SEM), an energy dispersive x-ray spectrometer (EDX) and x-ray diffraction (XRD). Water uptake, methanol permeability and membrane conductivity tests were also carried out. By reducing the membrane swelling ratio and methanol permeation, the single μDMFC with the modified Nafion®117 membrane produced reasonable power density performance as high as 4.9 mW cm−2 under 2 M methanol solution at room temperature.

Design and Fabrication of a Silicon-based Direct Methanol Fuel Cell

The design and fabrication for a novel silicon-based micro direct methanol fuel cell (mu-DMFC) of 0.64cm2 active area on <100> silicon wafer are described in this paper. The novelty of the DMFC structure is that the anodic micro channels arranged in the asymmetric mesh have been fabricated, and the first objective of the experimental trials is to verify the feasibility of the novel structure on the basis of MEMS technology. The effect of different operating parameters on mu-DMFC performances is experimentally studied for two different flow field configurations (grid and spiral). Preliminary testing results show that this novel mu-DMFC demonstrates the better performances using 2M methanol solution feed at room temperature, and the output characteristics of mu-DMFC with the grid flow field exceed the one with the spiral flow field. Results have demonstrated a maximum output power density of about 2.3mW/cm2 using 2M methanol solution

MEMS-based micro direct methanol fuel cell using microfabrication technology

The microfabrication and performance of a micro direct methanol fuel cell (μDMFC) by silicon processes are presented in this paper. Using the silicon micromachining techniques, including thermal oxidation, optical lithography, wet etching, silicon anodization, physical vapor deposition, electroless plating, laser beams cauterization, and anodic bonding, we have successfully made single μDMFC as small as 10mmx8mmx3mm. The main reason for the use of MEMS technology is the prospective potential for miniaturization and economical mass production of micro direct methanol fuel cells. The double side of silicon wafer deep wet etching was employed for the gas channels and fuel chamber preparation. The formation of porous silicon (PS) layers for electrode supports by electrochemical process is the key technologies to improve the MEMS-based μDMFC. The method of catalyst deposition reported here differs from previous work in the specific method of electroless plating Pt-deposition and platinum with ruthenium (Pt-Ru) co-deposition on the porous silicon substrates. The power density of the single cell reached only 2.5mW/cm2 lower than that single cell with traditional MEA (4.9mW/cm2) at the same operation conditions, but further improved performance of the μDMFC with the electro-catalytic electrodes is expectant. Moreover, using the MEMS technology makes the batch fabrication of μDMFC much easier and can reduce the usage of rare metals.

Performance research of a silicon-based micro direct methanol fuel cell

The design and fabrication for a novel silicon-based micro direct methanol fuel cell (μ-DMFC) of 0.64cm2 active area on <100> silicon wafer are described in this paper. The novelty of the DMFC structure is that the anodic micro channels arranged in the asymmetric mesh have been fabricated, and the first objective of the experimental trials is to verify the feasibility of the novel structure on the basis of MEMS technology. The effect of different operating parameters on μ-DMFC performances is experimentally studied for two different flow field configurations (grid and spiral). Preliminary testing results show that this novel μ-DMFC demonstrates the better performances using 2M methanol feed at room temperature, and the output characteristics of μ-DMFC with the grid flow field exceed the one with the spiral flow field. Results have demonstrated a maximum output power density of about 2.3mW/cm2 using 2M methanol solution.