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Archer Group published in Science Advances demonstrating a novel solution to CO2 emission mitigation

Monday, July 25, 2016

Energy forecasts show that fossil fuels will continue to play a major role in meeting worldwide energy demands, at least in the short and midterm. To capitalize on the high energy density of fossil fuels, the incorporation of carbon capture, utilization, and sequestration (CCUS) technologies is essential to reduce global CO2 emissions. Large-scale adoption of classical CCUS technologies is currently limited by the additional energy requirements associated with CO2 capture, resulting in higher cost of energy and difficulties in transporting and sequestering the captured CO2. Additionally, the thermodynamic and kinetic stability of CO2 complicates the conversion to useful chemicals. Wajdi Al Sadat joined the Archer Group with a good understanding of the technical challenges associated with classical CCUS, working for more than 10 years in the oil/gas industry and having demonstrated the feasibility of carbon capture on vehicles.

The Archer Group has been studying the impact of incorporating CO2 in metal/O2 batteries, showing a dramatic increase in discharge capacity. The group confirmed the production of carbonates when using lithium, sodium and magnesium anodes. Building on the group’s experience, Wajdi demonstrated the concept for aluminum/CO2-O2 batteries. The game changer is that when using a specific ionic liquid-based electrolyte, the electrochemical system reduces CO2 to oxalate, a feedstock to useful chemicals in many industries including pharmaceutical, fiber and metal smelting. In addition to the production of a useful product, the electrochemical system produces considerable amount of energy (13 A/gCarbon at 1.4 V). Electrochemical and analytical techniques revealed the O2 is electrochemically reduced to from superoxide radicals that reduce CO2 when the CO2:O2 ratio is high, to produce aluminum oxalate.  

Since the system operates as a primary electrochemical system, the continuous introduction of aluminum is needed, which in itself is associated with CO2 emissions. To determine whether the proposed electrochemical system can uptake more CO2 from flue gas streams than that produced during the aluminum anode mining, refining and production processes, a high-level life cycle assessment (LCA) was conducted. The study confirmed that the electrochemical system is capable of reducing CO2 emissions at rate of up to 3.5 kg CO2/kg Al.

Reference: Wajdi I. Al Sadat and Lynden A. Archer. The O2-assisted Al/CO2 electrochemical cell: A system for CO2 capture/conversion and electric power generation. Sci. Adv. 2:e1600968 (2016) DOI: 10.1126/sciadv.1600968

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