Water-Soluble, Air-Stable Fluoflavine Derivatives Used for Electrochemical Carbon Removal and Flow Battery Energy Storage
1 October 2026
Affiliation
NUS
Focus topic
CO2 Capture
Electrochemically Induced Carbon Dioxide Capture from Air with an Aqueous Fluoflavine Molecule
Summary
In simulated flue gas containing 10% CO2 and 10% O2, the oxygen-tolerant, water-soluble sorbent (FFDS) for direct air capture (DAC) system maintained stable capture–release over 38 cycles and 200 h, achieving an average CO2/e⁻ ratio of 0.88, 99.02% Coulombic efficiency, and 36.7 mL CO2 released per cycle. Increasing current density from 20 to 100 mA cm-2 reduced CO2 release time from 50 to 20 min, with energy consumption of 58–190 kJ mol-1 CO2.
Indoor DAC operated for 40 days, while accelerated overnight DAC achieved approximately 99% Coulombic efficiency over 16 cycles, with 97% of FFDS remaining intact. Doubling FFDS concentration doubled capture capacity to >46 mL CO2 per cycle under both indoor and outdoor conditions.
The estimated total DAC energy demand was 3.37–6.36 GJ tonne-1 CO2.
What makes this novel compared to best-in-class technology?
To our knowledge, FFDS is the first aqueous oxygen-tolerant, redox-flow sorbent to demonstrate reversible electrochemical CO2 capture under simulated flue gas containing 10% O2. In direct air capture, it delivers ~90% Coulombic efficiency, representing the highest reported value among flow-battery materials for electrochemical carbon capture.
TRL Level
1-3
Relevant for
Coal-fired power plants, cement and steel plants, waste-to-energy facilities, industrial sites with oxygen-containing flue gas, modular direct-air-capture facilities using aqueous flow systems
About
Inventors: Yan Jing, Zhuwen Wei, Sheng Xu
Affiliation: National University of Singapore (NUS), Department of Materials Science and Engineering
Publication: Wei, S. Xu, J. Liu, K. Zhu, M. Tang, A. Li, X. Wang, K.P. Tan, Y. Li, Z. Meng, Y. Jing, Electrochemically induced carbon dioxide capture from air with an aqueous fluoflavine molecule. ACS Energy Lett, 2025, 10.1021/acsenergylett.5c03881.
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