A direct methanol fuel cell has large activation losses at both the anode and the cathode, whereas for most fuel cell types the cathode losses dominate. There are also considerable losses relating to fuel crossover. Produce an equation for the cell voltage at any current density for the direct methanol fuel cell. Figure 6.1 on page 143 should give you an idea of what you are aiming for.

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Direct Methanol Fuel Cells Cell voltage (V) 1.2- 1.0 0.8 0.6 0.4 0.2- 0 0 50 Performance to be expected from a good hydrogen-fuelled PEMFC Typical performance from a good direct methanol single cell 100 150 Current density (mA cm-²) 200 Power = 60 mW cm-² 250 143 Figure 6.1 Voltage/current density graph for 2003 state-of-the-art direct methanol FC operating under ambient conditions. Direct Methanol Fuel Cells Cell voltage (V) 1.2- 1.0 0.8 0.6 0.4 0.2- 0 0 50 Performance to be expected from a good hydrogen-fuelled PEMFC Typical performance from a good direct methanol single cell 100 150 Current density (mA cm-²) 200 Power = 60 mW cm-² 250 143 Figure 6.1 Voltage/current density graph for 2003 state-of-the-art direct methanol FC operating under ambient conditions.