Fuel cells and method of operation

A liquid electrolyte fuel cell with means (202) to define an electrolyte chamber (208), and comprising two electrodes (10): an anode (10a) on one side of the electrolyte chamber (208) and a cathode (10b) on the other side. The anode (10a) comprises a sheet (1 1 ) of metal through which are defined a multiplicity of through- holes (14), and a gas-permeable layer (16) comprising fibrous and/or particulate electrically-conductive material which is bonded to and in electrical contact with the sheet (1 1 ) of metal, and is hydrophobic, and a second fluid-permeable layer (18) comprising fibrous and/or particulate electrically-conductive material and catalytic material, which is bonded to the outer surface of the gas-permeable layer (16), and is less hydrophobic than the first gas-permeable layer (16). The fuel cell (200) also comprises means (26, 50, 44) to adjust the pressure difference between electrolyte (20) within the electrolyte chamber (208) and a gas exposed to the surface of the anode (10a) remote from the electrolyte chamber (208), so that an interface between the electrolyte (10) and the gas is at an intermediate position within the second fluid- permeable layer (18). Raising the anode gas pressure above the electrolyte pressure has been found to improve long-term performance of the cell.