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

• Published in: Angewandte Chemie International Edition Vol. 56; no. 11; pp. 2893 - 2897
• Main Authors: Han, Sang‐Beom, Kwak, Da‐Hee, Park, Hyun Suk, Choi, In‐Ae, Park, Jin‐Young, Kim, Si‐Jin, Kim, Min‐Cheol, Hong, Seongho, Park, Kyung‐Won
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 06.03.2017
• Edition: International ed. in English
• Subjects: carbon felt; Density; Electrochemistry; Fuel cells; Fuel technology; nitrate; Nitrate reduction; Nitrates; Nuclear fuels; Oxidation; polymer electrolyte; Proton exchange membrane fuel cells; redox couples; Regenerative fuel cells
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201610738

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. Need to NO: A chemically regenerative redox fuel cell uses the NO3−/NO redox couple as a liquid catalyst at a carbon‐felt cathode. The reduced NO(g) is regenerated to NO3− by O2. It gave a power density of 512 mW cm−2 at 0.8 V, twice the target power density of 250 mW cm−2 at 0.8 V in the H2/O2 proton exchange membrane fuel cells (PEMFCs).