Catalyst boosts prospects for fuel-cell vehicles

Also, a source of CO 2 is required at the cathode (usually recycled from anode exhaust) to form the carbonate ion, representing additional BoP components.High contact resistances and cathode resistance limit power densities to around 100 -200 mW/cm 2 at practical operating voltages. Solid Oxide Fuel Cell (SOFC)The electrolyte in this fuel cell is a solid, nonporous metal oxide, usually Y 2 O 3 -stabilized ZrO 2 .The cell operates at 600-1000 °C where ionic conduction by oxygen ions takes place.Typically, the anode is Co-ZrO 2 or Ni-ZrO 2 cermet, and the cathode is Sr-doped LaMnO 3 .Early on, the limited conductivity of solid electrolytes required cell operation at around 1000 °C, but more recently thin-electrolyte cells with improved cathodes have allowed a reduction in operating temperature to 650 -850 °C.Some developers are attempting to push SOFC operating temperatures even lower.Over the past decade, this has allowed the development of compact and high-performance SOFC which utilized relatively low-cost construction materials.Concerted stack development efforts, especially through the U.S. DOE's SECA program, have considerably advanced the knowledge and development of thin-electrolyte planar SOFC.As a consequence of the performance improvements, SOFCs are now considered for a wide range of applications, including stationary power generation, mobile power, auxiliary power for vehicles, and specialty applications. Key Parameter Typical Requirements Expected fuel cell performancePower output 12 -42 V DC is acceptable for most applications, 110 / 220 V AC may be desirable for powering power tools etc. H H O CO (a) O C O ( ) °F F ½ c CO + O CO 2 2 ½ → E = E + (RT/ 2 ) ln [P / P ] + (RT/ 2 ) ln [P ]