Deployment of An in-Membrane Micro Fuel Cell for Portable Applications

Advances in nano/microfabrication technology has led to the deployment of smaller , faster , and more efficient portable , wireless , and autonomous devices. Today’s devices have significantly improved multitasking and computing capability that leads to increased energy requirements. These devices currently rely on secondary batteries like the Ni-Cd , Li-ion , and Li-polymers as a power source , but the need for constant replacement and recharging , interrupted operation , disposal issues , and increasing power requirements have prompted the development of alternative power sources like polymer electrolyte fuel cells as replacements. Fuel cells are high energy power sources that produce DC electricity directly from the stored chemical potential in their fuel and oxidant input. A conventional Nafion-based polymer electrolyte membrane (PEM) fuel cell is a sandwich-like stack of separate layers that facilitate electronic , protonic , and fluid transport.  In the conventional micro PEM fuel cell , the auxiliary layers that serve as flow field , current collectors , and reactant distributors contribute significantly to the size and weight of the device leading to bulkier devices.  New planar type micro fuels cell architectures have recently emerged where proton conduction is in-plane versus the traditional through-plane orientation. These planar micro fuel cells can facilitate the deployment of thinner and reduced form factor power sources. Distinct from previously fabricated micro fuel cells by other researchers , in this work we present a novel micro fuel cell design where the micro-flow channels for fuel and oxidant input and the membrane electrode assembly (MEA) are fabricated entirely within a Nafion membrane. Nafion is the most widely used membrane in fuel cells that utilize a polymer electrolyte due to its superior properties. The fabrication process leverages electron beam lithography and dry etching for Nafion patterning and this new fuel cell design can result in the use of fewer materials for the deployment of a low-weight , high energy density power source.