We demonstrate state-of-the-art room temperature operation of silicon microchannel-based micro-direct methanol fuel cells (mu DMFC) having a very high fuel use efficiency of 75.4% operating at an output power density of 9.25 mW cm(-2) for an input fuel (3 M aqueous methanol solution) flow rate as low as 0.55 mu L min(-1). Inaddition,an output power density of 12.7 mW cm(-2) has been observed for a fuel flow rate of 2.76 mu L min(-1). These results were obtained via the insertion of novel hydrophilic macroporous layer between the standard hydrophobic carbon gas diffusion layer (GDL) and the anode catalyst layer of a mu DMFC: the hydrophilic macroporous layer acts to improve mass transport, as a wicking layer for the fuel, enhancing fuel supply to the anode at low flow rates. The results were obtained with the fuel being supplied to the anode catalyst layer via a network of microscopic microchannels etched in a silicon wafer. (c) 2008 Elsevier B.V. All rights reserved.