Advanced Mediator Architectures for Efficient Electron Transfer in Enzymatic Fuel Cell Electrodes

Our objective is to develop advanced mediator architectures for efficient electron transfer in enzymatic fuel cells (EFCs) for low power systems. The proposed EFC will leverage ongoing research at both CFDRC and Michigan State University to provide a fully-integrated lightweight, low-cost, manufacturable, and renewable power supply, for various military and civilian applications. EFC systems offer several advantages over the conventional electrochemical power sources: higher energy density, low-cost and environmentally-friendly catalysts, room temperature and pH neutral operating environment, a variety of renewable fuels (e.g. sugars). In Phase I, we will demonstrate easy-to-synthesize novel mediators with tunable redox potential. In addition we will develop a well-controlled electrodeposition process and finally demonstrate a mediated glucose anode integrated with CFDRC’s existing EFC. In Phase II we will finalize development of the mediator and deposition techniques and create a computational modeling based design tool to obtain maximal anode performance for a given enzyme and fuel with stable and reproducible operation. The fully-integrated prototype will be capable of providing a proof-of-concept demonstration as a portable military power source. A multi-disciplinary team with proven expertise in electrochemical power sources, biomicrosystems, bioelectrochemistry, and system design has been assembled to accomplish these goals. BENEFIT: The major outcome of Phase II will be an enzymatic fuel cell with a state-of-the-art immobilized mediator for a reproducible high performance power source. The use of the improved mediator will provide reproducible high power performance and reduced time to market. Furthermore, the novel mediator developed here will have advantages of performance and manufacturing (immobilized versus diffused) over our existing mediator solution. The fully integrated system will meet a critical need in many small, mobile military systems, which are typically limited by batteries, and their inconvenient replacement/recharge requirements. The high power EFC device proposed here eliminates these limitations by taking advantage of readily available sugar sources of more than ten times higher energy density in biocatalytic oxidation. Immediate military applications for the Phase II device include micro air vehicles (MAVs), unattended ground sensors (UGSs), and wireless surveillance networks. Additionally with some adaptation, the device could be suitable for implantation to meet the military’s vision of remote surveillance through the use of insects and other animals. While the initial development is focused on military markets, there exist parallel commercial efforts including monitoring of plants, bridges, and highways. In the implantable area, the EFC could be adapted for implantable medical devices such as pacemakers and drug delivery pumps. The Phase II program will be tailored to incorporate the requirements of lightweight, low-cost, and manufacturable needed to make commercialization possible.