Abstract: A system and method for estimating an amount of carbon support loss in fuel cells of a fuel cell stack in a vehicle, for example, during vehicle off-times. The system and method include estimating an amount of time that a hydrogen concentration in the fuel cell stack is zero and calculating an amount of carbon loss based on the amount of time that the hydrogen concentration in the fuel cell stack is zero.

Abstract: Fuel-cell assemblies containing a membrane electrode assembly, methods for preparing the membrane electrode assembly, and methods for functionalizing catalytic surfaces of catalyst particles in the membrane electrode assembly of the fuel cell assembly have been described. The fuel-cell assemblies and their membrane electrode assemblies contain cathode catalyst materials having catalytic surfaces that are functionalized with cyano groups to improve catalyst activity. The cathode catalyst materials may include a catalytic metal such as platinum or a platinum alloy. The cyano groups may be derived from a cyanide source that is electro-oxidized onto the catalytic surfaces. Nonlimiting examples of cyanide sources include amino acids such as glycine, alanine, and serine.

Abstract: A system and method for estimating an amount of carbon support loss in fuel cells of a fuel cell stack in a vehicle, for example, during vehicle off-times. The system and method include estimating an amount of time that a hydrogen concentration in the fuel cell stack is zero and calculating an amount of carbon loss based on the amount of time that the hydrogen concentration in the fuel cell stack is zero.

Abstract: Fuel-cell assemblies containing a membrane electrode assembly, methods for preparing the membrane electrode assembly, and methods for functionalizing catalytic surfaces of catalyst particles in the membrane electrode assembly of the fuel cell assembly have been described. The fuel-cell assemblies and their membrane electrode assemblies contain cathode catalyst materials having catalytic surfaces that are functionalized with cyano groups to improve catalyst activity. The cathode catalyst materials may include a catalytic metal such as platinum or a platinum alloy. The cyano groups may be derived from a cyanide source that is electro-oxidized onto the catalytic surfaces. Nonlimiting examples of cyanide sources include amino acids such as glycine, alanine, and serine.

Abstract: A system and method for recovering cell voltage loss in a PEM fuel cell stack that include operating the stack at conditions that provide excess water that flushes away contaminants deposited on the cell electrodes. Two techniques are described that both operate the stack at a relatively low temperature and a cathode inlet RH above saturation. The first technique also includes providing hydrogen to the anode side of the stack and air to the cathode side of the stack, and operating the stack at a relatively low cell voltage. The second technique also includes flowing hydrogen to the anode side of the stack and nitrogen to the cathode side of the stack, using an external power source to provide a stack current density, and providing an anode humidity level that is significantly higher than the cathode humidity level.

Abstract: A fuel cell electrocatalyst layer having increased voltage cycling durability. The electrocatalyst layer comprises annealed platinum particles having an average particle size diameter from about 3 to about 15 nm deposited on a support structure. The platinum particles are annealed at a temperature from about 800 to about 1,400° C. for a time period such that the surface area is reduced by about 20% as compared to the original surface area. In various embodiments, the electrocatalyst layer retains an electrochemical surface area that is greater than 50% of an original electrochemical surface area after about 15,000 voltage cycles in the range from about 0.6 to about 1.0 V.