The hydrogen bromine (H2-Br2) fuel cell system is an attractive system for electrical energy storage because of its high round-trip conversion efficiency, high power density capability, and anticipated low costs. The hydrogen-bromine fuel cell system can be operated in the acid or alkaline modes as shown by below ...postprin

Chan, GKY

Konwar, D

Nguyen, TV

Yarlagadda, V

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Title Alkaline-based hydrogen bromine fuel cellAuthor(s) Nguyen, TV; Yarlagadda, V; Konwar, D; Chan, GKYCitation The 2014 Annual Meeting of the AES Electrophoresis Society(AIChE), Atlanta, GA., 16-21 November 2014.Issued Date 2014URL http://hdl.handle.net/10722/234145Rights This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.The hydrogen bromine (H2-Br2) fuel cell system is an attractive system for electrical energy storage because of its high round-trip conversion efficiency, high power density capability, and anticipated low costs. The hydrogen-bromine fuel cell system can be operated in the acid or alkaline modes as shown by below. Acid-based H2-Br2 System Negative: H2 ?? 2H+ + 2e-, Positive: Br2 + 2e- ?? 2Br-,  (Eored = 0.0V) (Eored = 1.09V ) Acid System Membrane H+ 2Br- + 2H+ ?? 2HBr ====================================== Overall: H2 + Br2 ?? 2HBr + electricity, Eo= 1.09V Alkaline-based H2-Br2 System  Negative: H2 + 2K+OH- ?? 2H2O + 2K+ + 2e-, Postive: Br2 + 2e- ?? 2Br-, (Eored = -0.83V) (Eored = 1.09V) Alkaline System Membrane K+ 2Br- + 2K+ ?? 2KBr  ========================================= Overall: H2 + 2KOH + Br2 ?? 2KBr + 2H2O + electricity, Eo= 1.92V Figure 1 shows schematics of the cell configuration of these two systems. The main difference is the additional compartment for KOH solution between the negative electrode and the membrane for the hydrogen reactions. The alkaline H2-Br2 fuel cell was studied recently by us because of its advantages over the acid system such as higher cell potential, low cost catalyst for the hydrogen evolution and oxidation reactions and lower corrosivity. The results from that study confirmed that this system can deliver a higher cell voltage and that the reaction rates of the hydrogen and bromine reactions in alkaline solution (KOH) were as fast as in acid solution (HBr). The results also showed that high power density performance could be obtained and its current performance was limited by high cell internal resistance, due mainly to high ionic resistance of the potassium ion (K+) conducting membrane. [1] This presentation will discuss new development in the alkaline H2-Br2 fuel cell. Acidic System Alkaline System HBr/Br2 In KOH In KBr/Br2 In H2 In H2 In H2 Out H2 Electrode (single phase) Br2 Electrode HBr/Br2 Out H2 Out H2 Electrode (two phase) KOH Out Br2 Electrode KBr/Br2 Out   Figure 1. Cell configurations of the acid and alkaline H2-Br2 fuel cell systems Reference: 1) T.V. Nguyen, V. Yarlagadda, G. Lin, G. Weng, C.-Y. Li, and K.-Y. Chan, “Comparison of Acid and Alkaline Hydrogen-Bromine Fuel Cell Systems,” ECS Transactions, Vol. 58, No. 37 (2014). Acknowledgements This work was funded by the National Science Foundation through grant number EFRI-1038234 and Research Grants Council of Hong Kong through a General Research Fund (GRF HKU 700210P).  

Alkaline-based hydrogen bromine fuel cell

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