The present invention discloses a fuel supply for a fuel cell, the fuel cell including a liquid storage area that includes a liquid reactant, a reaction area that includes a solid reactant, wherein the liquid reactant is pumped into the reaction area such that the liquid reactant reacts with the solid reactant to produce reaction components, a product collection area that receives the reaction components, a barrier, and a container with an interior volume that substantially encloses the reaction area, liquid storage area, product collection area. The barrier separates and defines several of the aforementioned areas, and moves to simultaneously increase the product collector area and decrease the liquid storage area as the liquid reactant is pumped from the liquid storage area and the reaction components are transferred into the product collection area.