N‐doped Carbon CoOx Nanohybrids: The First Precious Metal Free Cathode to Achieve 1.0 W/cm2 Peak Power and 100 h Life in Anion‐Exchange Membrane Fuel Cells

Efficient and durable nonprecious metal electrocatalysts for the oxygen reduction (ORR) are highly desirable for several electrochemical devices, including anion exchange membrane fuel cells (AEMFCs). Here, a 2D planar electrocatalyst with CoOx embedded in nitrogen-doped graphitic carbon (N-C-CoOx) was created through the direct pyrolysis of a metal organic complex with a NaCl template. N-C-CoOx showed high ORR activity, with excellent half-wave (0.84 V vs. RHE) and onset (1.01 V vs. RHE) potentials. This high intrinsic activity was translated to operating AEMFCs (containing radiation-grafted polymer electrolyte materials), with the N-C-CoOx catalyst able to achieve extremely high power density (1.05 W cm-2) and mass transport limiting current (3 A cm-2) for a precious metal free electrode. The N-C-CoOx cathode also showed excellent stability over 100 hours of operation at 600 mA/cm2 under H2/air (CO2-free) reacting gas feeds. The N-C-CoOx cathode catalyst was also paired with a very low loading PtRu/C anode catalyst, to create AEMFCs with a total PGM loading of only 0.10 mgPt-Ru cm-2 capable of achieving 7.4W mg-1PGM as well as supporting a current of 0.7 A cm-2 at 0.6 V with H2/air (CO2 free) – creating a cell that was able to meet the 2019 DOE target of initial performance of 0.6 V at 0.6 A cm-2 under H2/air with a PGM loading < 0.125 mg cm-2 with AEMFCs for the first time.