The Design and Investigation Zinc-Air Flow Battery with Automatic Control System (Phase II) JINGYU SI Mechanical Engineering Department University of Wisconsin–Milwaukee

Outline Introduction of zinc-air flow battery system Build up and test the reactor of zinc-air flow battery system Morphological study of the surface change on zinc particles in zinc slurry anode during charge/discharge Conclusion Future work

Introduction of zinc-air flow battery system WHY 01 WHAT 02 HOW 03

Energy densities for various types of batteries

Raw material costs

Zinc air battery Four major components Three main reactions Two key problems

Redox flow battery Distinct structure Unique features Low energy density

Zinc air flow battery system

Build up and test the reactor of zinc-air flow battery system Introduction of reactor The control component and algorithm Study the performance of reactor Study the durability of reactor

Reactor and reactor in system

The control component and algorithm

Polarization characteristics of for a single air-cathode reactor. Polarization characteristics of 1st and 2nd generation prototype with single air electrodes(0.95 cm2) at constant flowing rate

Test up to DoD 10% discharge on the lifespan of the 1st generation reactor Galvanostatic discharge up to 10% DoD of bi-air electrodes of 1st generation prototype at a current density of 40 mA cm-2 (respect to the geometric area of air cathode) constant flowing rate

Polarization characteristics of 2nd generation prototype Polarization characteristics of 2nd generation prototype with single air electrodes (2.16 cm2) at constant flowing rate for 6 days

Galvanostatic discharge 1 hour of single air electrodes of 2nd generation prototype Galvanostatic discharge 1 hour of single air electrodes of 2nd generation prototype at a current density of 100 mA cm-2 (respect to the geometric area of air cathode) constant flowing rate

Morphological study of the surface change on zinc particles in zinc slurry anode during charge/discharge Half-cell discharge(oxidation) and charge(reduction) test Morphology of the zinc particles in various DoD during oxidation in the half-cell setup. Morphology of zinc particle in cell partial (DoD 20%-DoD 30%) reduction-oxidation cycling in half-cell setup

Half-cell discharge(oxidation) and charge(reduction) test Three electrodes setup Zinc particle was on the top of flat disc electrode 6 M KOH electrolyte Potentiostatic oxidation/reduction

Morphology of the zinc particles in various DoD during oxidation in the half-cell setup B C D   DoD 0% DoD 10% DoD 20% DoD 30%

Morphology of zinc particle in cell partial (DoD 20%-DoD 30%) reduction-oxidation cycling in half-cell setup A B C D 3rd DoD 30% 4th DoD 30% 5th DoD 30% 6th DoD 30%

Conclusion The reactor with automatic control of rechargeable Zn-air flow battery has built up The reactor show the power density was up to 280mW cm-2 and the current density was up to 330 mA cm-2 at constant flowing rate  (at 1V cut-off voltage). The reactor shows the durability was up to 240 hours with little degradation. The 20%-30% DoD state of zinc particle anode would be  suitable for zinc- based rechargeable battery

More studies about electrolytes, air cathode and battery configuration are needed to further improve performance and stability The regenerator will be researched to charge the ZnO back to zinc without dendrites grow. The control algorithm for other components in system will be created and studied. Future work

Thank you Questions ?