A decade and half ago a group of scientests Calilfornia Institute of Technology (CIT) in vented a new type of fuel cell in which the proton conduction membrane of PEM fuel cells is replaced by a substance called a superprotonic solid acid. The result of this replacement is a new type of fuel cell called a solid acid fuel cell (SAF). SAF fuel cells operate at at temperature of 250C which is intermediate between PEM fuel cells (<120C) and solid oxide fuel cells (>800C). Unlike PEM fuel cells SAF cells do not require humidification and they are relatively tolerant of impurities (e.g. S and CO) which allows them to be operated using reformed hydrocarbon fuels. The 250 degree operating temperature also potentially allows the electrodes to use much lower loadings of platinum group metals in the electrodes thus leading to lower costs. On the other hand avoiding the high temperature of solid oxide fuel cells avoids some of the high costs associated with using exotic materials which can withstand high temperature operation.
However, as discussed at length in this paper the performance of state of the art SAF cells is still not good enough to allow them to complete with PEM fuel cells in most markets. SAFcell is a commercial spinoff from the CIT group, and they currently have plans to manufacture low power (100 watts or less) SAF cells for remote power and mobile power (i.e. military backpacks) applications. Apparently this is a performance niche in which the ability of the SAF cells run off reformed hydrocarbon fuels rather than highly purified hydrogen gives them an advantage over the more mature PEM fuel cells. Whether or not further advancements in this fuel cell technology will open other market niches remains to be seen.