ITM Power’s hydrocarbon fuel cell membrane is highly conductive and demonstrates a very high power density exceeding 1.5W/cm² at 600mV with hydrogen/air, 0.3mg/cm² of platinum catalyst per electrode and low gas pressures (1.5bar). Following achievement of these targets, ITM Power is undertaking an 18 month programme focusing on membrane durability and scale up to full automotive cell dimensions.
Three months into this programme, ITM Power’s membrane material has outperformed all targets against which it has been measured. A key metric among these is voltage retention in fuel cell open circuit mode. This is a universally recognized accelerated test for which the US Department of Energy (DoE) has established specific targets dictating that the cell voltage must not drop by more than 20% over 200 hours. Using an internationally recognised and commercially available fuel cell, a membrane electrode assembly containing ITM Power’s membrane material has repeatedly shown durability beyond 700 hours (representing many 1000’s of hours of normal operation). This represents over three times the longevity specified in the DoE target, and comparable with the best results measured for incumbent fluorocarbon membrane materials and as such is a significant indication of ITM Power’s fuel cell membrane durability.
In addition to maintaining open circuit voltage, the membrane also measured extremely low hydrogen cross over at circa 1mA/cm². This is close to an order of magnitude lower than that measured for incumbent fluorocarbon membrane materials.