Deterioration mechanism of the carbon-plastic electrode of the Zn-Br2 battery

✍ Scribed by Masayuki Futamata; Toshikazu Takeuchi

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 637 KB
• Volume: 30
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(92)90135-j

✦ Synopsis

The reactivity of bromine with graphite and polyethylene was studied to clarify the deterioration mechanism ofthe carbon plastic (CP) electrode ofthe ZnBr2 battery. At first, intercalation of bromine in highly oriented pyrolytic graphite (HOPG) was conducted in aqueous solution. Stages 2, 3, 4, and 5 bromine-graphite intercalation compounds (Br*-GICs) were obtained in 19-3,2.9-O.& 0.8-0.65, and 0.5 mol/l Br2 solutions, respectively, and analysed based on a linear diffusion theory. Apparent diffusion coefficients were found to be governed by the final stage structure. Bromine-GICs were electrochemically synthesised and decomposed in 3 mol/l ZnBr2 solution. Bromine-GICs were ascertained to be generated and decomposed during charge/discharge cycles of the Zn-Br2 battery. Repeated reaction of Br2 with pyrolytic graphite (PC), polyethylene (PE), and CP led to C-Br bond formation, along with exfoliation and cracking on the surface. Consequently, this reaction must be the reason for the mechanical deterioration of the CP electrode in the Zn-Br2 battery.