Electrochemical analysis on how structural and compositional modification of electrode affects power generation in reverse electrodialysis

초록

We suggest a modified Ti-based electrode for reverse electrodialysis to increase power density and retain long-term durability. Specifically, a mesh-type Ti electrode and electrochemically fabricated Pt/Ti electrode are employed in the reverse electrodialysis single cell. The electrode systems are compared in terms of power output, resistance, specific capacitance, and redox-couple reaction kinetics near the electrode surface. Among the electrodes, Pt/Ti mesh-embedded cell exhibits the highest j(max)(-16.13 A m(-2)) and P-max(-0.702 W m(-2)). The improvement in performance is ascribed to the reduced resistance associated with heterogeneous charge transfer and to the enlarged electrochemical surface area, verified by impedance analysis, and by monitoring the capacitive behavior of the electrodes, respectively. The highest exchange current density of Pt/Ti mesh electrode is attributed to facile electron transfer and reduced power loss in the electrode compartment. Furthermore, the Pt/Ti mesh electrode allows stable operation of reverse electrodialysis for an extended time. Finally, we demonstrate the power generation of a reverse electrodialysis stack built up with multiple pairs of ion exchange membranes for potential commercial application.

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