• Korean Membrane Journal
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• v.5 no.1
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• pp.1-9
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• 2003

Due to the increasing intelligence, the increasing connectivity, and always-on characteristics energy needs for the portable electronics cannot be managed by the state-of-art battery technology. Micro fuel cell fuelled by aqueous methanol is gaining lots of interest from the new energy storage developers since it has the potential to offer the longer operation time to the portable electronic devices. Although the technical barriers to the commercialization exit, it is expected that the micro fuel cell technology bring huge benefits to the current energy storage market once it matures. In the article, benefits, challenges and market players of the direct methanol fuel cell arena is briefly reviewed.

• Macromolecular Research
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• v.17 no.10
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• pp.729-733
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• 2009

Solution casting films of sulfonated poly[styrene-b-(ethylene-r-butylene)-b-styrene] copolymer (sSEBS)-based composite membranes that contained different amounts of organic, nanorod-shaped polyrotaxane were annealed at various temperatures for 1 h. The films' properties were characterized with respect to their use as polymer electrolyte membranes in direct methanol fuel cells (DMFCs). Different aspect ratios of polyrotaxane were prepared using the inclusion-complex reaction between $\alpha$-cyclodextrin and poly(ethylene glycol). The presence of the organic polyrotaxane inside the membrane changed the morphology during the membrane preparation and reduced the transport of methanol. The conductivity and methanol permeability of the composite membranes decreased with increasing polyrotaxane content, while the annealing temperature increased. All of the sSEBS-based, polyrotaxane composite membranes annealed at $140^{\circ}C$ showed a higher selectivity parameter, suggesting their potential usage for DMFCs.

• Macromolecular Research
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• v.14 no.2
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• pp.214-219
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• 2006

Cast Nafion-based composite membranes containing different amounts of organic, nanorod-shaped polyrotaxane were prepared and characterized, with the aim of improving the properties of polymer electrolyte membranes for direct methanol fuel cell applications. Polyrotaxane was prepared using the inclusion-complex reaction between ${\alpha}$-cyclodextrin and poly(ethylene glycol) (PEG) of different molecular weights. The addition of polyrotaxane to Nafion changed the morphology and reduced the crystallinity. The conductivity of the composite membranes increased with increasing polyrotaxane content up to 5 wt%, but then decreased at higher polyrotaxane contents. Well-dispersed, organic polyrotaxane inside the membrane can provide a tortuous path for the transport of methanol, as the methanol permeability depends on the aspect ratio of polyrotaxane, which is controlled by the molecular weight of PEG. All of the Nafion-based, polyrotaxane composite membranes showed a higher selectivity parameter than the commercial Nafion films did.

• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.123-127
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• 2016

Methanol fuel cells having advantages of relatively favorable reaction kinetics and higher energy density have attracted increasing interests as best alternative to hydrogen fuel cell because of H2 production, storage and distribution issues. While there have been extensive research works on developing key components such as electrocatalysts as well as their physicochemical properties in practical formic acid fuel cells, there have also been urgent requests for investigating which fuel sources will be more suitable for direct liquid fuel cells in future. In this mini-review, we highlight the overall interest and outlook of formic acid fuel cells in terms of electrocatalysts, fuel supply and crossover, water management, fuel cell efficiency and system integration in comparison with methanol fuel cells.

• Journal of the korean Society of Automotive Engineers
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• v.7 no.2
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• pp.64-79
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• 1985

Engine performances and emission characteristics were investigated, using a experimental single cylinder engine with methanol-LPG(butane) fuel blend. The results were compared with the case of neat methanol and gasoline. The blending ratio of methanol to LPG was reasonable at 90 : 10(M90) and in using M90, the engine performances including output, brake specific fuel consumption and brake thermal efficiency, were better than those of neat methanol and gasoline. CO emission of M90 was lower than that of meat methanol by 15% and lower than that of gasoline by 35%. HC emission of M90 was also lower than that of gasoline by 46-85% in the whole range of .phi. The concentration of NOx emission of M90 was lower than that of gasoline and higher than that of neat methanol.

• Bulletin of the Korean Chemical Society
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• v.29 no.4
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• pp.842-846
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• 2008

Layer-by-layer assembled multilayers of poly(ethersulfone)s were deposited on the surface of Nafion membrane for the application of direct methanol fuel cells (DMFC). Aminated poly(ethersulfone) (APES) and sulfonated poly(ethersulfone) (SPES) were used as a polycation and a polyanion for fabrication of the multilayer films. UV/Vis absorption spectroscopy verified a linear build-up of the multilayers of APES and SPES on the surface of Nafion. Thin multilayer films deposited on the Nafion membrane enabled methanol permeability of the membrane to decrease by 78% in comparison with the pristine Nafion. The performance of DMFCs in concentrated methanol was highly enhanced by using the multilayer modified Nafion.

• Macromolecular Research
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• v.16 no.5
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• pp.457-466
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• 2008

The relation between the phase separated morphologies and their transport properties in the polymer blend membrane for direct methanol fuel cell application was studied. In order to enhance the proton conductivity and reduce the methanol crossover, sulfonated poly(arylene ether sulfone) copolymer, with a sulfonation of 60 mol% (sPAES-60), was blended with nonsulfonated poly(ether sulfone) copolymer (RH-2000, Solvay). Various morphologies were obtained by varying the drying condition and the concentration of the casting solution (10, 15, 20 wt%). The transport properties of proton and methanol molecule through the polymer blend membranes were studied according to the absorbed water. AC impedance spectroscopy was used to measure the proton conductivity and a liquid permeability measuring instrument was designed to measure the methanol permeability. The state of water in the blend membranes was confirmed by differential scanning calorimetry and was used to correlate the morphology of the membrane with the membrane transport properties.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.143.2-143.2
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• 2010

Therefore, with this development assignment we'd like to develop the hybrid system combining 800W DMFC (Direct Methanol Fuel Cell) and 1.6kW of Lithium secondary battery pack which can be applied to the most common small cart. a scooter, to secure the development capability of hundreds of Watts DMFC, the high-capacity Lithium secondary battery pack, the technology of BMS (Battery Management System) and the development technology of hybrid system. DMFC, in fact, has lower energy efficiency than PEMFC (Polymer Electrolyte Membrane Fuel Cell); however, it has several advantages in terms of fuel storage and use. It is pretty easy to be stored and used without any additional colling and heating devices because of its insensitive liquid methanol to temperature. In conclusion, DMFC system is the most suitable device for small mobile vehicles.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.505-506
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• 2008

The direct methanol fuel cell (DMFC) is a promising power source for portable applications due to many advantages such as simple construction, compact design, high energy density, and relatively high energy-conversion efficiency. In this work, an electrochemical methanol sensor for monitoring the methanol concentration in direct methanol fuel cells was fabricated using a thin composite nafion membrane as the electrolyte. We have analyzed the I-V characteristic of the fabricated methanol sensor as a function of methanol concentration, catalyst electrode and platinum(Pt) dot.

• Carbon letters
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• v.4 no.3
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• pp.121-125
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• 2003

The Pt-Ru/Carbon as an anode catalyst supported on the commercial activated carbon (AC) having high surface area and micropore was characterized for application of Direct Methanol Fuel Cell (DMFC). The Pt-Ru/AC anode catalyst used in this experiment showed the performance of $600\;mA/cm^2$ current density at 0.3 V. The borohydride reduction process using $NaBH_4$, denoted as a process A, showed much higher current and power densities than process B prepared by changing the reduction and washing process of process A. The particle sizes are strongly affected by the reduction process than the specific surface area of raw active carbon and the sizes are almost constant when the specific surface area of carbon are over than the $1200\;m^2/g$. Smaller particle size of catalyst and more narrow intercrystalite distance increased the performance of DMFC.