NOVELTY - A stack (10) of fuel cells (11) for generating electrical current from streams of hydrogen-containing reducing fluid and oxygen-containing oxidant reactant, comprises barrier (32) to acid migration secured to the land region of each separator plate assembly and extending away from the adjacent edge (30) of each separator plate assembly in a direction away from the flow channels.    USE - As stack of fuel cells for generating electrical current from streams of hydrogen-containing reducing fluid and oxygen-containing oxidant reactant (claimed); used in transportation vehicles, portable power plants, or as stationary power plants.    ADVANTAGE - The stack of fuel cells prohibits acid migration from fuel cell, using a barrier to acid migration.    DETAILED DESCRIPTION - A stack (10) of fuel cells (11) for generating electrical current from streams of hydrogen-containing reducing fluid and oxygen-containing oxidant reactant, comprises each cell having a cathode electrode (12) and an anode electrode (14) secured adjacent opposed planar surfaces of a matrix plate (16) configured to hold a liquid acid electrolyte; separator plate assemblies (18), each secured in contact with the cathode electrode of one of the cells and the anode electrode of an adjacent cell, each separator plate assembly defining a first flow field (20) adjacent a first contact surface (22) of the separator plate assembly, the first flow field including at least one first flow channel (24) extending inwardly from the first contact surface between ribs (24A, 24B) of the separator plate assembly to direct a corresponding one of the reactant streams adjacent a selected one of the electrodes; and the ribs of each separator plate assembly adjacent and parallel to an adjacent edge (30) of the separator plate assembly comprising a land region (28) extending along the first contact surface (22) between the flow channel and the adjacent edge of the separator plate assembly, and extending parallel to the at least one flow channel; a barrier (32) to acid migration secured to the land region of each separator plate assembly and extending away from the adjacent edge of each separator plate assembly in a direction away from the flow channels. An INDEPENDENT CLAIM is included for method involving prohibiting migration of a liquid acid electrolyte between fuel cells in a stack, involving securing a barrier to acid migration within the land region and extending away from the adjacent edge of the separator plate assembly in a direction away from the flow channel.    DESCRIPTION OF DRAWING(S) - The figure shows a perspective view of fuel cell.    Stack (10)    Fuel cells (11)    Cathode electrode (12)    Anode electrode (14)    Matrix plate (16)    Barrier (32)