Direct methanol fuel cell

A method for generating power using a direct methanol fuel cell comprising a unit cell having an electrolyte membrane, an anode on one surface of said electrolyte membrane, and a cathode on the other surface of said electrolyte membrane, said anode comprising an anode catalyst layer and an anode diffusion layer, said anode catalyst layer being in contact with a surface of said electrolyte membrane, said anode diffusion layer being in contact with a surface of said anode catalyst layer opposite to said surface of said anode catalyst layer in contact with said electrolyte membrane,

• said method comprising the steps of:
• (a) selecting an anode diffusion layer and an electrolyte membrane such that a methanol flux value JGDM of said anode diffusion layer and a methanol flux value JPEM of said electrolyte membrane, which are measured by allowing said anode diffusion layer and said electrolyte membrane to come into contact with an aqueous solution having a certain methanol concentration at a certain temperature, satisfy the following relations:
• JGDL=1×10−5 to 5×10−4 mol/(cm2·min.), (i)
• and
• JPEM×JGDL≦1×10−8 [mol/(cm2·min.)]2;
• (ii)
• (b) determining a concentration of methanol to be contained in fuel and a temperature for operating said fuel cell based on the temperature and the methanol concentration used for said measurement of said JGDL and said JPEM;
• and
• (c) generating power at said temperature determined in said step (b) by feeding fuel containing methanol at the concentration determined in said step (b) to said anode.