Enhancement of Bromine Kinetics Using Pt@Graphite Felt and Its Applications in Zn-Br 2 Redox Flow Battery

Abstract

The high surface area electro-catalysts facilitate the enhanced electrochemical reactions by providing more active sites. Here, introducing noble Pt particles on the active electrode (graphite felt) highly improved the reaction kinetics of positive redox couple (Br2/Br−) in a zinc bromine flow battery. The noble Pt metal significantly improvises the electron transfer reaction between bromine and Pt loaded GF. The graphite felt modification process was carried out by simple synthesis process. The Pt content was optimized based on the enhancement of the reaction kinetics of Br2/Br−. The electrode with ∼1% Pt at the electrode showed a maximum specific power density of 1640 mW cm−2. The flow cell at low loading of Pt also delivered an excellent cycling performance over 300 cycles. The flow cell delivered maximum Coulombic and Energy efficiency of ∼96, ∼83%, respectively even at 300th cycle. It is clearly seen that the cell having optimum content of Pt on the electrode surface is proved as suitable positive electrode for obtaining good performance of Zn-Br2 flow cell.