The invention provides a fuel cell system, such as a direct methanol fuel cell (DMFC) that uses passive approaches to thermal-fluids management. In accordance with one embodiment of the invention, a fuel cell is provided that uses a passive fuel delivery system. In accordance with another embodiment of the invention, a fuel cell is provided that passively transports water from the cathode or an external source to the anode. In accordance with still another embodiment of the invention, a fuel cell is provided that passively directs heat to an evaporation pad to facilitate evaporation of fuel. In accordance with still another embodiment of the invention, a fuel cell is provided that provides passive carbon dioxide gas management.