An Active and Robust Air Electrode for Reversible Protonic Ceramic Electrochemical Cells

Abstract

Reversible protonic ceramic electrochemical cells (R-PCECs) are a promising option for efficient and low-cost generation of electricity and hydrogen. Commercialization of R-PCECs, however, hinges on the development of highly active and robust air electrodes. Here, we report an air electrode consisting of PrBa 0.8 Ca 0.2 Co 2 O 5+δ and in situ exsolved BaCoO 3−δ nanoparticles (PBCC−BCO) that shows minimal polarization resistance (∼0.24 Ω cm 2 at 600 °C) and high stability when exposed to humidified air with 3−50% H 2 O. An R-PCEC utilizing PBCC-BCO demonstrates remarkable performances at 600 °C: achieving a peak power density of 1.06 W cm −2 in the fuel cell mode and a current density of 1.51 A cm −2 at 1.3 V in an electrolysis mode. More importantly, the R-PCECs demonstrate an exceptionally high durability over 1833 h of continuous operation in the electrolysis mode. This work offers an efficient approach to design of high-performance and durable electrodes for R-PCECs.

Nanocomposites: A New Opportunity for Developing Highly Active and Durable Bifunctional Air Electrodes for Reversible Protonic Ceramic Cells

“…Solid oxide cells (SOCs) are extremely promising for grid‐scale energy conversion and storage, as they can convert the chemical energy from a wide range of fuels into electrical power in fuel cell mode, with far higher thermodynamic efficiencies and lower emissions than conventional combustion‐based systems. [ 2–5 ] SOCs can also operate reversibly, storing electrical energy through water‐splitting and storage of hydrogen gas in electrolysis mode. In addition, fuel cell storage capacity is independent of device size, and limited only by fuel storage tank volume, posing a significant advantage over rechargeable batteries.…”

“…SOCs can be either oxygen‐ (O‐SOC) or proton‐ (H‐SOC) conducting, depending on electrolyte composition. [ 2,5,10,11 ] In particular, solid oxide electrolysis cells based on proton‐conducting electrolytes (PCECs) have three unique advantages over conventional (oxygen ion‐conducting) solid oxide electrolysis cells (O‐SOECs). First, the lower activation energy of proton conduction compared to oxygen conduction results in lower operating temperatures for PCECs than O‐SOECs.…”

Theoretical and Experimental Investigations on K‐doped SrCo0.9Nb0.1O3‐δ as a Promising Cathode for Proton‐Conducting Solid Oxide Fuel Cells

“…Table 4 summarizes the power output and polarization of P‐SOFCs using different cobalt‐based perovskite cathodes in literature reports and this study [15–21] . One can see that the performance of the cell in this study using KSCN−BCZY cathode is promising compared with previous reports.…”

La-doped Ba0.5Sr0.5Co0.8Fe0.2O3- d as Cathode for Protonic-Conducting Solid Oxide Fuel Cells with Enhanced Structure Stability

“…As we previously reported, the oxygen chemical bulk diffusion coefficient, Dchem, and chemical oxygen surface exchange coefficient, kchem, of BSCF at 700  C are 2*10 -5 cm 2 S -1 and 4*10 -4 cm S -1 , respectively (12). Both the bulk diffusion coefficient and the surface exchange coefficient of BSCF are about one order of magnitude higher than those of classic electrocatalyst La0.6Sr0.4Co0.8Fe0.2O3- (LSCF) at the same temperature: 6.4*10 -6 cm 2 S -1 for kchem and 1.3*10 -5 cm S -1 for Dchem, respectively (13), and are comparable with those of PrBaCo2O5+ which is the state-of-the-art electrocatalyst for PCFCs cathodes (1*10 -5 cm -2 S -1 for Dchem and 1*10 -4 cm S -1 for kchem, respectively) (2,14). Therefore, BSCF is an excellent ORR electrocatalyst.…”

“…Regarded as one of the clean and efficient energy conversion devices, proton-conducting solid oxide fuel cells (PCFCs) have drawn increasing attention and demonstrated potential application at intermediate temperatures (500-700  C) (1,2). Unlike oxygen ion-conducting SOFCs (O-SOFCs), in PCFCs, water is formed on the cathode side.…”