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Wednesday, August 23, 2023

Novel Zinc Air Primary Cell


                                                       A Chinese vendor ( Amazon) sells these small wax-coated zinc flower pots resembling "refuse cans".  I use ethyl acetate solvent to easily de-wax the inside exposing the fresh zinc surface.  20% Aq. Na OH electrolyte and steel wool wrapped in paper towel. Open voltage ids 1.18V with a hefty short circuit 750 mA. it rebounds quickly.

The wax protects the outer zinz and the cell may very well be a secondary ( re-chargeable). Study in progress. 



UPDATE (7-23-23):   Below, are images of simple bench-scale prototypes for Zinc-Air cell studies:



    A Chinese company sells these inexpensive wax-coated Zinc flower pots on Amazon. I remove the inside wax ( and cup lip for electrode contact). I leave the outside wax in place to avoid electrolyte leak. The electrolyte is 20% aq. KOH.  I place test cathode solids such as activated carbon, zeolite and halloysite clay inside the cup being sure to have the zinc surface covered with paper towel to avoid a short. The zinc is the anode and the solid the test cathode for O2 adsorption from the air.



                          Zinc surface  presented for test cell performance after solvent removal of the wax.

                          Samples of activated carbon, halloysite clay and zeolite prepafred for testing. 1.33 V ( overpotential is observed after cell is assembled with electrolyte. I use a graphite electrode for current collection. It is poster board painted with polystyrene in toluene with graphite added. The electrode is conductive.

                        The activated carbon ( expected) adsorbs O2 fro the aq. solution and air. The zeolite dod not fuction but... the nanotubular halloysite clay was impressive. It is a member of the kaolin clay family. i did not test kaolin (white clay) yet, but do not expect current to be generated.


Whe testing is completed, remove contents from can and cut sections for use in other zinc applications such as... nickel-zinc cells.  I will post data on this zinc -air cell as we generate data on performance. The halloysite clay is from Idaho, USA.   This clay has "energy-storage" possibilities!

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