Abstract: Disclosed is a fuel cell system wherein the flow of fuel and oxygen is optimized thereby improving the thermal efficiency of the entire system. The fuel cell system comprises at least one stack for generating electrical energy by an electrochemical reaction between hydrogen gas and oxygen, a fuel supply portion for supplying fuel to the stack, and an oxygen supply portion for supplying oxygen to the stack. The stack is formed in a stacked configuration with MEAs and separators. The separators are positioned on either surface of the MEAs. The separators have a plurality of ribs proximate to the MEAs which define a plurality of channels wherein the ratio of a width of the channels to the width of the ribs is from about 0.8 to 1.5.

Abstract: Disclosed is a method of preparing a positive active material for a rechargeable lithium battery including adding first and second compounds to a solvent to prepare an acidic solution with a pH from 0.

Abstract: A process of manufacturing a positive active material for a lithium secondary battery includes preparing a coating-element-containing organic suspension by adding a coating-element source to an organic solvent, adding water to the suspension to prepare a coating liquid, coating a positive active material with the coating liquid, and drying the coated positive active material.

Abstract: Disclosed is a positive active material for a rechargeable lithium battery, including a lithiated intercalation compound and an additive compound. The additive compound comprises one or more intercalation element-included oxides which have a charging voltage of 4.0 to 4.6V when 5-50% of total intercalation elements of the one or more intercalation element-included oxides are released during charging.

Abstract: The present invention relates to a negative active material for a lithium rechargeable battery and a method of preparing the same, and the negative active material prepared by coating a carbon source with a coating liquid, and drying the carbon source, and the negative active material comprises a core having a carbon source with surface-treatment layer formed on the surface of the core, the surface-treatment layer having at least one compound of coating element selected from the group cosnsisting of amorphous, semi crystalline, or crystalline hydroxides, oxyhydroxides, oxycarbonates, and hydroxidecarbonates.

Abstract: A membrane-electrode assembly for a mixed reactant fuel cell system is provided. The membrane-electrode assembly does not require a separator that physically separates the membrane-electrode assemblies from each other in a stack. The membrane-electrode assembly of the present invention instead includes an electrode substrate that is disposed on a surface of an anode or a cathode of the membrane-electrode assembly. The electrode substrate has a flow path, through which a fuel and an oxidant are supplied. The fuel and oxidant are absorbed into the electrode substrate and further into the anode and the cathode. The fuel and the oxidant are selectively oxidized and reduced in the anode and the cathode, respectively, to produce electricity.

Abstract: A stack for a mixed oxidant fuel cell and a mixed oxidant fuel cell system including the stack. The stack includes at least one membrane-electrode assembly that includes a polymer electrolyte membrane, an anode and a cathode disposed on opposite sides of the polymer electrolyte membrane, and an electrode substrate disposed on at least one of the anode or the cathode; and an oxidant supply path and a fuel supply path that penetrate the membrane-electrode assembly. The oxidant supply path has both ends open, and the fuel supply path has one end open and the other end closed. The stack of the present invention can improve fuel cell efficiency by smoothly supplying a fuel and an oxidant. Particularly, since the stack is configured to supply the fuel and the oxidant without using a pump, it can make a fuel cell small and light.

Abstract: The polymer electrolyte membrane of the present invention includes a porous supporter having pores, and a metal ion adsorptive material and a proton conductive polymer which are present in the pores of the porous supporter.

Abstract: An active material for a battery has a surface treatment layer that includes a conductive agent and at least one coating-element-containing compound selected from the group consisting of a coating-element-containing hydroxide, a coating-element-containing oxyhydroxide, a coating-element-containing oxycarbonate, a coating-element-containing hydroxycarbonate, and a mixture thereof.

Abstract: A fuel cell stack includes a first separator and a second separator, each separator having raised portions and channel portions on a first side and a second side, the channel portions on the first side being opposite the raised portions on the second side and the channel portions on the second side being opposite the raised portions on the first side. The stack also includes a membrane-electrode assembly located between the first separator and the second separator, and closely contacting the raised portions of the first side of the first separator and the raised portions of the second side of the second separator.

Abstract: An active material for a battery has a surface treatment layer that includes a conductive agent and at least one coating-element-containing compound selected from the group consisting of a coating-element-containing hydroxide, a coating-element-containing oxyhydroxide, a coating-element-containing oxycarbonate, a coating-element-containing hydroxycarbonate, and a mixture thereof.

Abstract: There is provided a stack of a fuel cell system in which one or more electricity generators including separators disposed at both sides of a membrane-electrode assembly are stacked, the stack comprising heat releasing means for releasing heat generated from the electricity generators. The heat releasing means have different heat release rates depending on the positions of the associated electricity generators in the stack. In particular, the heat releasing means associated with the electricity generators located near the center of the stack have a higher heat release rate in order to maintain a more even temperature gradient across the stack.

Abstract: A fuel cell stack includes at least one electric generator with a membrane electrode assembly and separators placed at both sides of the membrane electrode assembly. A plurality of common passages are arranged at a surface of at least one of the separators to permit the flow of oxygen and a coolant. A guide is formed at an inlet of the common passage to guide the oxygen and the coolant into the common passage.

Abstract: The metal separator for a fuel cell of the present invention includes a metal substrate having reactant flow pathways and an electro-conductive anti-corrosion coating layer. The electro-conductive anti-corrosion coating layer covers the surface of the metal substrate on which the reactant flow pathways are formed. The coating layer may include metal carbides, metal oxides, and metal borides. A metal layer for improving adherence is formed between the surface of the metal substrate on which the reactant flow pathways are formed, and the electro-conductive anti-corrosion coating layer.

Abstract: A metal separator for a fuel cell of the present invention includes a metal substrate having a reactant flow pathway, and a metal nitride coating layer. The metal nitride coating layer covers the surface of the metal substrate on which a reactant flow pathway is formed and slurry-coated. A metal layer for improving adherence is formed between the surface of the metal substrate on which a reactant flow pathway is formed, and the electro-conductive metal nitride coating layer. The metal separator is suitable for a fuel cell since it is lightweight, and has excellent anti-corrosion and electric conductivity.

Abstract: A fuel cell system including: at least one electricity generator for generating electric energy through a reaction between fuel and oxygen and for discharging the remaining fuel; a fuel supply unit for supplying a predetermined amount of fuel to the electricity generator; an oxygen supply unit for supplying oxygen to the electricity generator; a valve unit which is connected to a fuel discharger of the electricity generator and which adjusts a fuel pressure in the electricity generator; a sensor unit which is disposed in the electricity generator and which senses an output amount of electricity of the electricity generator; and a control unit which converts a sensed signal from the sensor unit into a predetermined control signal and which controls the valve unit with the predetermined control signal.

Abstract: A cooling system for a fuel cell stack is provided. The fuel cell stack includes an electricity generating assembly having a plurality of unit cells, wherein each of the unit cells comprises common passages. An oxidant used to generate electric energy and a coolant used to cool the stack may both flow through the common passages.

Abstract: A positive active material for a rechargeable lithium battery is provided. The positive active material includes a core having a lithiated compound and at least two surface-treatment layers on the core, and each of the two surface-treatment layers includes at least one coating element. Alternatively, the positive active material includes at least one surface-treatment layer on the core, wherein the surface treatment at least comprises at least two coating element-included oxides.

Abstract: The separator of the present invention includes a substrate with a flow path channel formed thereon, and a hydrophobic coating layer formed in the flow path channel. The separator for a fuel cell, which is suggested in the present invetnion, can easily discharge water generated at a cathode because the hydrophobic coating layer is formed only in the flow path channel.

Abstract: A method of preparing for a positive active material for a rechargeable lithium battery is provided. In this method, a lithiated compound to be coated and an organic solution or aqueous solution including a coating-element source are putted into a mixer, the mixture is continuously stirred to mix the contents thoroughly, and a hot dry gas is introduced into the mixer to evaporate the solvent while the powder is continuously agitated. The resulting dry coated powdery compound is heat-treated at an elevated temperature to obtain an oxide coating on the lithiated compound.