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Gallant, Betar M. Byun, Gi Hyun Massachusetts Institute of Technology. Department of Mechanical Engineering 2025-03-24T18:48:55Z 2025-03-24T18:48:55Z 2025-02 2025-02-21T19:21:15.629Z https://hdl.handle.net/1721.1/158875 As the unprecedented temperature rise originating from anthropogenic carbon dioxide (CO₂) emission intensifies, the development of post-combustion carbon capture technologies has been urged. Although its maturity, conventional thermal swing processes using aqueous amines, suffer from significant limitations, including high energy requirements and sorbent degradation. Electrochemical CO₂ capture technologies, which use electrical energy instead of thermal energy, have emerged as an energy efficient way to capture CO₂. This shift not only improves energy efficiency but also reduces reliance on fossil fuels, further contributing to reduction in CO₂ emissions. This work explored the potential of electrochemical metal oxide formation for CO₂ capture, a promising alternative to amine-based systems due to its exceptional sorbent (i.e., metal oxide) stability. Li₂O in eutectic mixture of potassium nitrate (KNO₃) and lithium nitrate (LiNO₃) was chosen as a case study due to the relatively well-understood chemistry of the system and the potential synergistic effects between metal oxide and the molten salt. Primarily, we investigated the synergistic effect of Li₂O in nitrate molten salt via thermal gravimetric analysis. Next, electrochemically produced Li₂O by reduction of oxygen gas was tested as a CO₂ sorbent while investigating parameters affecting its conversion to lithium carbonate (Li₂CO₃). Through this study, we suggested dissolution model as a crucial pathway for conversion. Lastly, we explored the effect of adding nitrite ion (NO₂⁻) to the molten salt. Irreversible side reaction between NO₂⁻ and CO₂ was confirmed with X-ray diffraction and NOₓ measurement. This thesis demonstrates the feasibility of electrochemical metal oxide-based CO₂ capture, highlighting some considerations in the capture step. S.M. Massachusetts Institute of Technology Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) Copyright retained by author(s) https://creativecommons.org/licenses/by-sa/4.0/ CO₂ Capture with Lithium Oxide in Molten Salt Media : A Case Study of CO₂ Capture via Electrochemically Produced Metal Oxide Thesis application/pdf Master Master of Science in Mechanical Engineering Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="732f2a91-23ee-4425-acf4-3b228059040b"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Title>CO₂ Capture with Lithium Oxide in Molten Salt Media : A Case Study of CO₂ Capture via Electrochemically Produced Metal Oxide</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2025-02</PublicationDate> <Authors> <Author> <DisplayName>Byun, Gi Hyun</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>https://creativecommons.org/licenses/by-sa/4.0/</License> <Abstract>As the unprecedented temperature rise originating from anthropogenic carbon dioxide (CO₂) emission intensifies, the development of post-combustion carbon capture technologies has been urged. Although its maturity, conventional thermal swing processes using aqueous amines, suffer from significant limitations, including high energy requirements and sorbent degradation. Electrochemical CO₂ capture technologies, which use electrical energy instead of thermal energy, have emerged as an energy efficient way to capture CO₂. This shift not only improves energy efficiency but also reduces reliance on fossil fuels, further contributing to reduction in CO₂ emissions. This work explored the potential of electrochemical metal oxide formation for CO₂ capture, a promising alternative to amine-based systems due to its exceptional sorbent (i.e., metal oxide) stability. Li₂O in eutectic mixture of potassium nitrate (KNO₃) and lithium nitrate (LiNO₃) was chosen as a case study due to the relatively well-understood chemistry of the system and the potential synergistic effects between metal oxide and the molten salt. Primarily, we investigated the synergistic effect of Li₂O in nitrate molten salt via thermal gravimetric analysis. Next, electrochemically produced Li₂O by reduction of oxygen gas was tested as a CO₂ sorbent while investigating parameters affecting its conversion to lithium carbonate (Li₂CO₃). Through this study, we suggested dissolution model as a crucial pathway for conversion. Lastly, we explored the effect of adding nitrite ion (NO₂⁻) to the molten salt. Irreversible side reaction between NO₂⁻ and CO₂ was confirmed with X-ray diffraction and NOₓ measurement. This thesis demonstrates the feasibility of electrochemical metal oxide-based CO₂ capture, highlighting some considerations in the capture step.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>