High-Performance Chemically Regenerative Redox Fuel Cells Using a NO3- /NO Regeneration Reaction

Abstract

In this study, we proposed high-performance chemically regenerative redox fuel cells (CRRFCs) using NO₃^- /NO with a nitrogen-doped carbon-felt electrode and a chemical regeneration reaction of NO to NO₃^- via O₂ . The electrochemical cell using the nitrate reduction to NO at the cathode on the carbon felt and oxidation of H₂ as a fuel at the anode showed a maximal power density of 730 mW cm^-2 at 80 °C and twofold higher power density of 512 mW cm^-2 at 0.8 V, than the target power density of 250 mW cm^-2 at 0.8 V in the H₂ /O₂ proton exchange membrane fuel cells (PEMFCs). During the operation of the CRRFCs with the chemical regeneration reactor for 30 days, the CRRFCs maintained 60 % of the initial performance with a regeneration efficiency of about 92.9 % and immediately returned to the initial value when supplied with fresh HNO₃ .

Keywords: carbon felt; fuel cells; nitrate; polymer electrolyte; redox couples.