CHARACTERIZATION AND DEVELOPMENT OF A SINGLE FLUID, PRIMARY FLOW BATTERY WITH SIMULTANEOUS HYDROGEN AND ELECTRICITY OUTPUTS

The objective of this work was to characterize and develop a single fluid, membraneless, primary flow battery chemistry with simultaneous hydrogen and electricity outputs. This work proposed three separate chemical equations for initial aluminum oxide layer removal, hydrogen generation at the aluminum anode, and the electrochemical equation. The chemical equations for initial aluminum oxide layer removal and hydrogen generation at the aluminum anode were sourced from literature, while the novel electrochemical equation was proposed based on experimentally observed phenomena. Additionally, a separate novel, high specific energy battery chemistry was explored with a gallium-indium alloy disposed on the aluminum anode surface, which sufficiently disrupted the aluminum oxide layer without the use of sodium hydroxide. The proposed set of chemical equations for the single fluid, membraneless, primary flow battery chemistry drove development of the specific energy mechanistic model which computed parameters such as specific energy, energy distribution between hydrogen and electricity, electricity and hydrogen production per square centimeter, round trip energy efficiency, and cost per kWh delivered. The specific energy mechanistic model was later expanded to include an applications and design specifications calculator; the calculator incorporated empirical chemistry parameters and user needs to generate a preliminary battery system design with supporting hardware specifications. Three different multi-cellular battery topologies were evaluated for scaled up, multi-cellular, prototype battery systems. The bipolar cell topology successfully demonstrated nearly 100% linearity for both open circuit voltage and electrical areal power metrics in laboratory characterization testing; the bipolar cell topology was selected for multi-cellular battery system design. A 300W bipolar battery system demonstrated 97.72% of expected open circuit voltage and 93.15% of expected electrical areal power, which further reinforced the claim that the 300W system was a successful multi-cellular embodiment of the bipolar cell topology.