122nd General Meeting of the KCS

Type Symposium
Area Recent Trends in Physical and Analytical Electrochemistry
Room No. Room 320
Time FRI 09:20-:
Code ELEC2-1
Subject Large-scale reverse electrodialysis operated by water electrolysis in neutral-pH water
Authors Jihyung Han, Namjo Jeong1, Chan-Soo Kim1,*
Marine Energy Convergence & Integration Laboratory, Korea Institute of Energy Research, Korea
1Korea Institute of Energy Research, Korea
Abstract Reverse electrodialysis (RED) produces electric power from mixing sea water with river water, with the stack voltage increasing proportionally up to several dozens of volts as the number of ion exchange membranes increases. Under these conditions, water electrolysis is a realistic redox reaction to convert ion flow into electron flow, because voltage loss by electrode resistance is much smaller than the total stack voltage. In this study, RED system includes a high membrane voltage from more than 50 cells, neutral-pH water as the electrolyte, and an artificial NaCl solution as the feed water, which is more universal, economical, and eco-friendly than that reported previously. We demonstrate that even though there is no specific method to reduce the overpotential for water electrolysis, large stack voltage with more than 50 cells can utilize the water oxidation/reduction in neutral-pH media as the electrode reaction in RED systems. All hydrogen gas produced at maximum power of RED is collected using a batch-type electrode chamber without electrolyte circulation and its production rate is 1.1 x 10-4 mol cm-2 h-1, which is larger than previously reported values for RED-driven hydrogen production. Therefore, when a pilot-scaled RED consisting of hundreds of cell pairs is operated, water electrolysis in neutral-pH electrolyte can be an effective redox reaction to produce not only electric power but also hydrogen energy. Overall, we expect this RED system to stimulate the sustainable energy community and the eco-friendly hydrogen economy, providing a new paradigm for future research initiatives. This research was supported by the Technology Development Program to Solve Climate Changes of the National Research Foundation (NRF) funded by the Ministry of Science, ICT & Future Planning (2017M1A2A2047366).
E-mail jihyung0760@kier.re.kr