NOVELTY - A fuel cell comprises anode side, cathode side, and solid electrolyte membrane, which is a proton conductive membrane with pore diameter smaller than 30 nm. The membrane comprises (vol.%) electrically nonconductive inorganic powder (5-60), acid or aqueous acid solution (10-90), and polymeric binder (5-50, preferably 12-40). The powder has good acid absorption capacity.    USE - Useful as primary battery, or electrochemical engines for converting chemical energy from fuel oxidation reaction to electrical energy.    ADVANTAGE - The inventive fuel cell uses membrane that is easily wet, and it does not need any mechanism for membrane humidification. It eliminates hydrophilic wick to wick liquid water to the membrane, thus simplifying the cell construction. It is produced from low-cost components with acceptable life and performance. The acid solution flow system of the inventive cell prevents changes in electrolyte concentration during fuel cell operation.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for (A) a method for preparing a catalyst layer for use in fuel cell (1100); (B) a hybrid power source comprising liquid feed fuel cell, direct current (DC) to DC converter, and rechargeable battery; (C) a method for reducing crossover current in a fuel cell; and (D) an oxidation fuel cell system. The catalyst layer is prepared by forming one monolayer of catalyst on the surface of nanosize inorganic powder, serving as nucleation site; forming additional catalyst layers on top of the first to obtain catalyst particles; and subsequently binding the obtained particles to the carbon backing layer and/or proton conducting membrane. The crossover current is reduced by sensing the level of the water or fuel in the water or fuel tank, and controlling the air or oxygen gas pressure. The system has anode chamber (1110), cathode chamber (1120), electrolyte membrane (1200), and fuel tank (1300). The anode chamber has anode (1112), fuel inlet (1114) and gas outlet (1116). The cathode chamber has cathode (1122) and oxygen or air inlet holes (1124). The fuel tank is divided by movable barrier (1310) into two parts. The first part (1312) contains the fuel or fuel solution and is connected to the anode chamber. The second part (1314) holds the gas with pressure greater than atmospheric pressure or having a closable gas inlet.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of an orientation independent hybrid power source.    Fuel cell (1100)    Anode chamber (1110)    Anode (1112)    Fuel inlet (1114)    Gas outlet (1116)    Cathode chamber (1120)    Cathode (1122)    Inlet holes (1124)    Electrolyte membrane (1200)    Fuel tank (1300)    Movable barrier (1310)    First part (1312)    Second part (1314)