Abstract: A fuel cell system in which a low open circuit voltage (OCV) is maintained in a start-up mode and in a shut-down mode, and a method of operating the same, the method including: supplying an anode off-gas and air to the cathode in an open circuit voltage state in a start-up mode and cutting off supply of the fuel gas to the cathode in a normal operating mode; and supplying the fuel gas and air to the cathode in a shut-down mode, and if a load is cut off, purging the cathode and the anode in the OCV state.

Abstract: A redox flow battery has a high energy density and an excellent charge and discharge efficiency because re-precipitation is prevented in an electrolyte solution or eduction is prevented in an electrode during reduction of a metal ion used as an electrolyte.

Abstract: A method of preparing an electrolyte membrane comprising a crosslinked object of a polybenzoxazine-based compound formed of a polymerized resultant product of a first monofunctional benzoxazine-based monomer or a second benzoxazine-based monomer multifunctional benzoxazine-based monomer with a crosslinkable compound.

Abstract: An electrolyte membrane includes a cross-linked reaction product of a benzoxazine monomer and a cross-linkable compound. The electrolyte membrane is impregnated with 300 to 600 parts by weight of phosphoric acid based on 100 parts by weight of the electrolyte membrane, and has a yield strain 0.5% or less, and a yield stress 0.3 MPa or less. The cross-linked material has a strong acid trapping ability with respect to the benzoxazine compound and excellent mechanical properties due to a cross-linkage. Also, the solubility of the cross-linked material in polyphosphoric acid is low, thereby showing excellent chemical stability. Accordingly, when the cross-linked material is used, an electrolyte membrane having an excellent liquid supplementing ability and excellent mechanical and chemical stability at a high temperature can be obtained.

Abstract: A method of removing residual oxygen in a residential high temperature non-humidification fuel cell stack including at least one cathode. The method includes making the pressure in the cathode higher than that outside of the cathode and maintaining airtight sealing of the cathode of the fuel cell stack, removing the residual oxygen in the fuel cell stack, and stopping supplying of fuel to the fuel cell stack. The setting of the pressure includes blocking air flow out of the cathode, comparing the pressure in the cathode with a set pressure higher than the pressure outside the cathode, and supplying air to the cathode until the pressure in the cathode is the same as or is higher than the set pressure.

Abstract: A crosslinked object of a polybenzoxazine-based compound formed of a polymerized resultant of a first monofunctional benzoxazine-based monomer or a second multifunctional benzoxazine-based monomer with a crosslinkable compound, an electrolyte membrane including the crosslinked object, a method of preparing the electrolyte membrane, and a fuel cell employing the electrolyte membrane including the crosslinked object.

Abstract: Crosslinked polybenzoxazines obtained by crosslinking a monofunctional first benzoxazine monomer and a multifunctional second benzoxazine monomer with a crosslinkable compound, an electrolyte membrane including the same, a method of preparing the electrolyte membrane, a fuel cell including the electrolyte membrane having the crosslinked polybenzoxazines using the method. The crosslinked polybenzoxazines have strong acid trapping capability, improved mechanical properties, and excellent chemical stability as it does not melt in polyphosphoric acid. Even as the amount of impregnated proton carrier and the temperature are increased, mechanical and chemical stability is highly maintained, and thus the electrolyte membrane can be effectively used for fuel cells at a high temperature.

Abstract: Crosslinked polybenzoxazines obtained by crosslinking a monofunctional first benzoxazine monomer and a multifunctional second benzoxazine monomer with a crosslinkable compound, an electrolyte membrane including the same, a method of preparing the electrolyte membrane, a fuel cell including the electrolyte membrane having the crosslinked polybenzoxazines using the method. The crosslinked polybenzoxazines have strong acid trapping capability, improved mechanical properties, and excellent chemical stability as it does not melt in polyphosphoric acid. Even as the amount of impregnated proton carrier and the temperature are increased, mechanical and chemical stability is highly maintained, and thus the electrolyte membrane can be effectively used for fuel cells at a high temperature.

Abstract: A method of preparing an electrolyte membrane comprising a crosslinked object of a polybenzoxazine-based compound formed of a polymerized resultant product of a first monofunctional benzoxazine-based monomer or a second benzoxazine-based monomer multifunctional benzoxazine-based monomer with a crosslinkable compound.

Abstract: A crosslinked object of a polybenzoxazine-based compound formed of a polymerized resultant of a first monofunctional benzoxazine-based monomer or a second multifunctional benzoxazine-based monomer with a crosslinkable compound, an electrolyte membrane including the crosslinked object, a method of preparing the electrolyte membrane, and a fuel cell employing the electrolyte membrane including the crosslinked object.

Abstract: A crosslinked object of a polybenzoxazine-based compound formed of a polymerized resultant of a first monofunctional benzoxazine-based monomer or a second multifunctional benzoxazine-based monomer with a crosslinkable compound, an electrolyte membrane including the crosslinked object, a method of preparing the electrolyte membrane, and a fuel cell employing the electrolyte membrane including the crosslinked object. The crosslinked object has a strong acid trapping capability with respect to the benzoxazine-based compound and high mechanical properties due to the crosslinking. The crosslinked object is very stable chemically because of elimination of solubility in polyphosphoric acid. The electrolyte membrane including the crosslinked object has excellent phosphoric acid supplementing capacity at a high temperature and mechanical and chemical stability.

Abstract: The present invention relates to a polymer electrolyte membrane that includes a porous polymer matrix and an ion conducting polymer coating membrane formed in the outer surface of single fibers in the porous polymer matrix. The polymer electrolyte membrane can provide excellent mechanical strength, is not deteriorated by heat even at a temperature higher than 100°C., can provide excellent ion conductivity even at non-humidified state. Thus it is suitable for use in a fuel cell that is operated at high temperatures.

Abstract: An electrolyte membrane includes a cross-linked reaction product of a benzoxazine monomer and a cross-linkable compound. The electrolyte membrane is impregnated with 300 to 600 parts by weight of phosphoric acid based on 100 parts by weight of the electrolyte membrane, and has a yield strain 0.5% or less, and a yield stress 0.3 Mpa or less. The cross-linked material has a strong acid trapping ability with respect to the benzoxazine compound and excellent mechanical properties due to a cross-linkage. Also, the solubility of the cross-linked material in polyphosphoric acid is low, thereby showing excellent chemical stability. Accordingly, when the cross-linked material is used, an electrolyte membrane having an excellent liquid supplementing ability and excellent mechanical and chemical stability at a high temperature can be obtained.

Abstract: An organic electrolyte solution for use in a redox flow battery and the redox flow battery including the organic electrolyte solution has a high energy density because re-precipitation is prevented in the organic electrolyte solution or eduction is prevented in an electrode during reduction of a metal ion used as an electrolyte.

Abstract: A redox flow battery has a high energy density and an excellent charge and discharge efficiency because re-precipitation is prevented in an electrolyte solution or eduction is prevented in an electrode during reduction of a metal ion used as an electrolyte.

Abstract: Provided are a polymer electrolyte membrane and a fuel cell including the same. The polymer electrolyte membrane has a phosphoric acid that is substituted with an aliphatic hydrocarbon. The polymer electrolyte membrane has excellent ion conductivity, heat resistance, and liquid-holding properties. The fuel cell including the polymer electrolyte membrane exhibits excellent performance.

Abstract: A polymer electrolyte membrane for use in a fuel cell and a method of producing a polymer electrolyte membrane. The method includes preparing a phosphate monomer solution by dissolving an initiator and a phosphate monomer containing at least one phosphoric acid group and at least one unsaturated bond in a solvent, impregnating a porous polymer matrix with the phosphate monomer solution, polymerizing the impregnated phosphate monomer, and impregnating the result of polymerization with a phosphoric acid.

Abstract: An electrolyte membrane includes a cross-linked reaction product of a benzoxazine monomer and a cross-linkable compound. The electrolyte membrane is impregnated with 300 to 600 parts by weight of phosphoric acid based on 100 parts by weight of the electrolyte membrane, and has a yield strain 0.5% or less, and a yield stress 0.3 Mpa or less. The cross-linked material has a strong acid trapping ability with respect to the benzoxazine compound and excellent mechanical properties due to a cross-linkage. Also, the solubility of the cross-linked material in polyphosphoric acid is low, thereby showing excellent chemical stability. Accordingly, when the cross-linked material is used, an electrolyte membrane having an excellent liquid supplementing ability and excellent mechanical and chemical stability at a high temperature can be obtained.

Abstract: A polymer electrolyte that may be used in a fuel cell includes sulfonated polyether ketone ketone and a cross-linking agent.

Abstract: Provided are method and apparatus for diagnosing the deterioration of a fuel cell. The method includes: controlling a frequency of current drawn from the fuel cell; calculating an AC impedance of the fuel cell by using a pulse component of output current of the fuel cell that is generated by the control of the frequency; and diagnosing the deterioration of the fuel cell based on the calculated AC impedance.