Journal Publication


Kang HoShin, Jehee Park, Sul Ki Park, Puritut Nakhaniveja, Soo Min Hwang, Youngsik Kim ,and Ho Seok Park

Journal of Industrial and Engineering Chemistry, Volume 72, 25 April 2019, Pages 250-254 (Website link)

img Herein, we report synthesis of Co3V2O8 nanoparticles for an electrocatalyst of seawater batteries. The cell using Co3V2O8 achieves a higher voltage efficiency of ∼76% than ∼72% of the cell without catalyst. In addition, the Co3V2O8 shows a good rate capability with reduced voltage gaps and an increased power density of ∼5.9 mW cm−2. This cell is stable over 20 cycles for 400 h with reduced voltage gap of ∼0.95 V. These findings are attributed to the facilitated redox kinetics of the clustered Co3V2O8 nanoparticles arising from the optimal metalOH bond strength and large surface area.

Hyuntae Bae, Jeong-Sun Park, S.T.Senthilkumar, Soo Min Hwang, and Youngsik Kim

Journal of Power Sources, 2019, 410-411, 99-105 (Website link)

img The water and carbon cycles are central to the Earth’s ecosystem, enabling the sustainable development of human societies. To mitigate the global issues of water shortages and climate change, we report a new electrochemical system that fulfills two functions—seawater desalination and carbon dioxide air-capture—during the charge and discharge processes. The seawater desalination-carbon capture system utilizes a seawater battery platform, consisting of three major compartments (desalination, sodium-collection, and carbon-capture), which are separated by sodium superionic conducting ceramic membranes. It is found that the concentrations of sodium ions and chloride ions in fresh seawater (total dissolved solids  34,000 ppm) are significantly decreased by the charging of the seawater desalination-carbon capture system, resulting in brackish water (total dissolved solids  7,000 ppm). The discharge process induces the air-capture of ambient carbon dioxide gases through carbonation reactions, which is demonstrated by the carbon dioxide gas removal in this compartment. The hybrid system suggests a new electrochemical approach for both desalination and carbon capture.

Yongil Kim, Guk-Tae Kim, Sangsik Jeong, Xinwei Dou, Chenxi Geng, Youngsik Kim, and Stefano Passerini

Energy Storage Materials, 2019, 16, 56-64 (Website link)

img A new electrolyte (anolyte) for the negative electrode of seawater batteries, based on the combination of two ionic liquids (ILs), a sodium salt, and a SEI-forming additive, is herein reported. The quaternary anolyte is composed of N-methyl-N-propylpyrrolidinium bis(fluorosulfonyl)imide (0.6 mol fraction), N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl) imide) (0.3 mol fraction), and sodium bis(fluorosulfonyl)imide (0.1 mol fraction). Ethylene carbonate (5 wt% with respect to the ILs and salt mixture) is added to promote SEI formation. The thermal, physicochemical, and electrochemical characterization of the quaternary electrolyte indicate its suitability as an anolyte, as well as the formation of a highly stable interface with the negative (hard carbon) electrode. Lab-scale seawater full cells employing a hard carbon anode and the ionic liquid-based quaternary anolyte show remarkable results in terms of capacity, cyclability, and rate capability at room temperature. Additionally, these cells showed better energy efficiency (voltage efficiency) and cyclability than those based on a conventional organic carbonate-based anolyte.