화학공학소재연구정보센터
Journal of the Electrochemical Society, Vol.162, No.6, A809-A819, 2015
Thermally Modified Graphite Electrodes for the Positive Side of the Zinc-Cerium Redox Flow Battery
In this study, thermal modification of graphite electrodes for the positive side of the Zinc-Cerium redox flow battery is found to enhance their performance and stability by providing a larger and more chemically active surface area to carry out the Ce(III)/(IV) reaction. Prolonged calcination (>9.5 h) and firing temperatures greater than 600 degrees C lead to a physical deterioration of the samples while at 300 degrees C no effect on the cerium reaction within the investigated reaction temperature range (25-55 degrees C) is evident. When treated at 600 degrees C for 6 h, the milder oxidation conditions result in a porous graphite electrode (7.13 m(2) g(-1)) with a low charge transfer resistance (0.14 m Omega cm(-2)) and negligible weight loss (W-TL = 6%). This thermally treated electrode is robust under repetitive cycling (300 cyclic voltammograms) with no degradation occurring within the time frame of the experiment (20 h). The quasi-reversible kinetics of the Ce(III)/(IV) reaction improve with elevated temperatures (k(o) = 6.0 x 10(-3) cm s(-1), D = 8.5 x 10(-6) cm(2) s(-1) and j(o) = 2.91 x 10(-3) A cm(-2)) and are comparable to the present electrode of choice on this flow battery, the Pt-Ti mesh electrode. (C) 2015 The Electrochemical Society. All rights reserved.