For traditional fuel cells to operate properly, water needs to be externally pumped from the cathode to the anode of the cell. MTI Micro, Albany, N.Y.
(mtimicrofuelcells.com), has developed several technologies that move the water needed for the process internally, eliminating the need for pumps, complicated recirculation loops, and other plumbing in direct methanol-fuel cells (DMFC).
MTI's methods let the cell carry 100% methanol and feed it uniformly across the anode.
In this DMFC, fuel concentration is usually controlled to about 2% methanol at the anode. Water needed at the anode to dilute the fuel is collected at the cathode and pumped externally to the anode, adding cost and size, and reducing energy density.
In this DMFC, diluted methanol is stored as fuel and pumping is simplified, but carrying fuel and water reduces the cell's energy density.