NOVELTY - A micro-electromechanical system (MEMS)-based fuel cell of the type using a fuel and an oxidant, the fuel cell comprises a substrate; an electrolyte in contact with the substrate; a cathode in contact with the electrolyte; an anode spaced apart from the cathode and in contact with the electrolyte; at least one chamber including an integral manifold for at least one of the fuel and oxidant; and an opening adapted for flow of at least one of the fuel and oxidant into the chamber.    USE - The MEMS-based fuel cell is used to convert a source fuel into an electric current.    ADVANTAGE - The present invention provides improved practical compact portable fuel cells with rapid startup times and improved efficiency and compact portable fuel cells with improved microscale manifolding of supplied fuel and/or supplied oxidant and with improved microscale manifolding for exhausting depleted oxidant and/or depleted fuel from the fuel-cell active region.    DETAILED DESCRIPTION - A MEMS-based fuel cell of the type using a fuel and an oxidant, the fuel cell comprises a substrate; an electrolyte in contact with the substrate; a cathode in contact with the electrolyte; an anode spaced apart from the cathode and in contact with the electrolyte; at least one chamber extending over at least a portion of at least one of the cathode and anode, the at least one chamber including an integral manifold for at least one of the fuel and oxidant; and an opening extending through the substrate under the chamber, the opening communicating with the chamber, where the opening is adapted for flow of at least one of the fuel and oxidant into the chamber. INDEPENDENT CLAIMS are:    (1) a manifold for a fuel cell having an electrolyte, an anode, and a cathode, the manifold comprising: a substrate; and an elongate roof affixed to the substrate and enclosing an elongate, generally semi-cylindrical interior volume communicating with the electrolyte and with at least one of the anode and cathode of the fuel cell; and    (2) a method for using a manifold in a MEMS-based fuel cell of the type using a fuel and an oxidant by providing a substrate carrying an electrolyte, a cathode in contact with the electrolyte, and an anode spaced apart from the cathode and in contact with the electrolyte; providing an integral manifold for at least one of the fuel and oxidant, the integral manifold extending over at least a portion of the electrolyte and at least a portion of one of the anode and cathode; and supplying at least one of the fuel and oxidant through the integral manifold to the electrolyte and to at least one of the anode and cathode.