Bromine overpotential

Metallic electrodes were less commonly used in RFBs because of the acidic and corrosive environment. In addition to noble metals, some metals with a high overpotential for gas evolution, such as Ni foam, have been used as substrate electrodes in several RFBs. Ni foam was first employed as a negative electrode and demonstrated 77.4% energy efficiency during 48 charge-discharge cycles in a sodium poly-sulfide/bromine RFB [16]. 

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