A collaborative analysis workforce, together with Los Alamos Nationwide Laboratory, College of Stuttgart (Germany), College of New Mexico, and Sandia Nationwide Laboratories, has developed a proton conductor for gasoline cells primarily based on polystyrene phosphonic acids that preserve excessive protonic conductivity as much as 200 C with out water. They describe the fabric advance in a paper printed this week in Nature Supplies. Hydrogen produced from renewable, nuclear, or fossil fuels with carbon seize, utilization, and storage may help to decarbonize industries and supply environmental, vitality resilience and suppleness throughout a number of sectors within the financial system. In direction of that, gasoline cells are a promising expertise that converts hydrogen into electrical energy by means of an electrochemical course of, emitting solely water.
“Whereas the commercialization of extremely environment friendly fuel-cell electrical automobiles has efficiently begun,” stated Yu Seung Kim, undertaking chief at Los Alamos, “additional technological improvements are wanted for the next-generation gasoline cell platform evolving in the direction of heavy-duty car purposes. One of many technical challenges of present gasoline cells is the warmth rejection from the exothermic electrochemical reactions of gasoline cells.
“We had been struggling to enhance the efficiency of high-temperature membrane gasoline cells after we had developed an ion-pair coordinated membrane in 2016,” stated Kim. “The ion-pair polymers are good for membrane use, however the excessive content material of phosphoric acid dopants triggered electrode poisoning and acid flooding once we used the polymer as an electrode binder.”
In present gasoline cells, the warmth rejection requirement is met by working the gasoline cell at a excessive cell voltage. To realize an environment friendly fuel-cell powered engine, the working temperature of gasoline cell stacks should enhance not less than to the engine coolant temperature (100 C).
“We believed that phosphonated polymers could be a very good different, however earlier supplies couldn’t be applied due to undesirable anhydride formation at gasoline cell working temperatures. So we’ve got centered on getting ready phosphonated polymers that don’t bear the anhydride formation. Kerres’ workforce on the College of Stuttgart was in a position to put together such supplies by introducing fluorine moiety into the polymer. It’s thrilling that we’ve got now each membrane and ionomeric binder for high-temperature gasoline cells,” stated Kim.
Ten years in the past, Atanasov and Kerres developed a brand new synthesis for a phosphonated poly(pentafluorostyrene) which consisted of the steps i) polymerization of pentafluorostyrene through radical emulsion polymerization and ii) phosphonation of this polymer by a nucleophilic phosphonation response. Surprisingly, this polymer confirmed a very good proton conductivity being increased than Nafion within the temperature vary >100°C, and an surprising wonderful chemical and thermal stability of >300°C.
Atanasov and Kerres shared their growth with Kim at Los Alamos, whose workforce in flip developed high-temperature gasoline cells to make use of with the phosphonated polymers. With the mixing of membrane electrode meeting with LANL’s ion-pair coordinated membrane (Lee et al. Nature Power, 1, 16120, 2016), the gasoline cells using the phosphonated polymer exhibited a superb energy density (1.13 W cm-2 below H2/O2 circumstances with > 500 h stability at 160 C).
What’s subsequent? “Reaching over 1 W cm-2 energy density is a important milestone that tells us this expertise might efficiently go to commercialization” stated Kim. Presently, the expertise is pursuing commercialization by means of the Division of Power’s ARPA-E and the Hydrogen and Gas Cell Applied sciences Workplace inside the Power Effectivity and Renewable Power Workplace (EERE).