Table 1.

US DOE technical targets for PEMs for transportation applications, adapted from Refs. [11,12,13].

Characteristics	2013 Status	2020 Targets
Maximum oxygen/hydrogen crossover *	<1.8 mA/cm2	2 mA/cm2
Maximum operating temperature	120 °C	120 °C
Membrane conductivity	0.002–0.04 S/cm	0.1 S/cm (120 °C)
		0.07 S/cm (Ambient)
		0.01 S/cm (−20 °C)
Area specific proton resistance at maximum	40 kPa: 0.023 Ω cm2	0.02 Ω cm2
Operating temperature and water partial pressures from 40 to 80 kPa	80 kPa: 0.012 Ω cm2
Minimum electronic area specific resistance		1000 Ω cm2
Cost	$18/m2	$20/m2
Durability (mechanical & chemical)	>20,000 cycles w/<10 sccm crossover, >2300 h	20,000 cycles w/<10 sccm crossover, 500 h

* Tested in MEA at 1 atm O₂ or H₂ at nominal stack operating temperature, humidified.