Shafaque Hisan W, Lee ChungHyuk, Fahy Kieran F, Lee Jason K, LaManna Jacob M, Baltic Elias, Hussey Daniel S, Jacobson David L, Bazylak Aimy
Thermofluids for Energy and Advanced Material Laboratory, Department of Mechanical and Industrial Engineering, Faculty of Applied Science and Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario M5S 3G8, Canada.
Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20878, United States.
ACS Appl Mater Interfaces. 2020 Dec 9;12(49):54585-54595. doi: 10.1021/acsami.0c14832. Epub 2020 Nov 25.
Despite the advantages of CO electrolyzers, efficiency losses due to mass and ionic transport across the membrane electrode assembly (MEA) are critical bottlenecks for commercial-scale implementation. In this study, more efficient electrolysis of CO was achieved by increasing cation exchange membrane (CEM) hydration via the humidification of the CO reactant inlet stream. A high current density of 755 mA/cm was reached by humidifying the reactant CO in a MEA electrolyzer cell featuring a CEM. The power density was reduced by up to 30% when the fully humidified reactant CO was introduced while operating at a current density of 575 mA/cm. We reduced the ohmic losses of the electrolyzer by fourfold at 575 mA/cm by fully humidifying the reactant CO. A semiempirical CEM water uptake model was developed and used to attribute the improved performance to 11% increases in membrane water uptake and ionic conductivity. Our CEM water uptake model showed that the increase in ohmic losses and the limitation of ionic transport were the result of significant dehydration at the central region of the CEM and the anode gas diffusion electrode-CEM interface region, which exhibited a 2.5% drop in water uptake.
尽管CO电解槽具有诸多优势，但由于质量和离子在膜电极组件（MEA）中的传输导致的效率损失，是商业规模实施的关键瓶颈。在本研究中，通过对CO反应物入口流进行加湿来增加阳离子交换膜（CEM）的水合作用，实现了更高效的CO电解。在配备CEM的MEA电解槽中，通过对反应物CO进行加湿，实现了755 mA/cm的高电流密度。当在575 mA/cm的电流密度下运行时引入完全加湿的反应物CO，功率密度降低了高达30%。通过对反应物CO进行完全加湿，我们在575 mA/cm的电流密度下将电解槽的欧姆损失降低了四倍。开发了一个半经验CEM水吸收模型，并用于将性能的提高归因于膜水吸收和离子电导率提高了11%。我们的CEM水吸收模型表明，欧姆损失的增加和离子传输的限制是CEM中心区域以及阳极气体扩散电极-CEM界面区域显著脱水的结果，该区域的水吸收下降了2.5%。
