Design of bio-based adhesives for fuel cell applications

Abstract

ABSTRACT Fuel cells contribute to decentralized and individually controllable energy supply. The low-temperature polymer electrolyte membrane fuel cell is ideal for both stationary and mobile use due to its low operating temperatures and superiority in discontinuous operation. Thermoplastics can be used as materials for bipolar halfplates, which have the advantage of low-cost manufacturing processes, as the components do not require cost-intensive post-processing due to their excellent corrosion resistance and electrical contacting. But the environmental conditions in operation pose a great challenge to the materials to be used: permanent humidity and sulphuric acid environment at 85°C, high required electrical conductivity and hydrogen impermeability. In order to demonstrate the potential of bio-based materials, adhesives for both sealing and conductive bonding of all joints within a fully bonded fuel cell are being developed and tested in an ongoing project. The epoxy resin systems developed can be both, one and two-component, and have different proportions of sustainable carbon. In addition, the fuel cell components, also consist of sustainable raw materials, so that bonding surfaces also pose a challenge. Results on the lap shear strength of the developed adhesives as well as on the durability of the adhesives under fuel cell environment are presented. Initial functional tests on bipolar plates bonded with proportionally bio-based raw materials show a functionality comparable to that of petroleum-based raw materials for epoxy adhesives.