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Saturday, August 26, 2023

Dragon Tree Watercolor. David S. Soriano


                                              "Dragon Tree". (2023). by David S. Soriano

                                                Creative Commons.  Use but credit artist.

Zinc/ Iodine/ Clay Secondary Cell Bench-scale Demo

   Carex has an interesting approach to creating a bench-scale  "zinc/ iodine" secondary cell using sand to absorb the formed molecular iodine:


I tried using "halloysite clay" ( kaolin family).  which is known to be microtubular and should absorb iodine well.  It does.  Of course, with a bench-scale prototype, we do not want iodine escaping into the air.



                        I am reaching 1.36 V with charging at 3 V/  100 mA for 3-4 minutes. Ashirt circuit sees the cell quickly rebound, a good sign.

My students will build these cells, obtain real-time acquisition and we will post our findings. We will use grafoil electrodes, activated carbon, zeolites, etc.  Try different sands and even grout cement!

 Follow the teachings and example of the great Michael Faraday!   Young minds will make their way to "energy-storage" and  "AI".  Ise Google's "bard" daily to help me organize my research thoughts.

Involvement is the key to future success.

Thursday, August 24, 2023

"The Direction Of Forces" A Poem by Bard ( AI/Google)


"The Direction of Forces"- Bard ( AI/Google)
Physics and chemistry, hand in hand,
Lead humans to a brighter land.
They develop new materials,
Design new energy storage systems,
And improve the efficiency of old ones.
They study the environmental impact,
Model the behavior, and test the performance.
They work tirelessly to find solutions
To the world's energy problems.
With their help, we can create a sustainable future
Where everyone has access to clean energy.
We can leave a better world for our children
And for generations to come.

Benchscale Simple Asymmetric Supercapacitor

 MnO2 / charcoal paste on grafoil electrode paired with MnO2 activated carbon paste on another grafoil electrode.  Aq. K2SO4 electrolyte. Sealed in plastic envelope with a small heating pad.  Two strips of steel screen stapled..... to the grafoil electrodes which are fragile.  About 1.0V with. measurable charge storage.  Will run e-loads and collect data. Will upload results.

Great for getting students started in important research on "energy- storage"!


                                                     Prep of a grafoil electrode ( polish surface of the grafoil gently to remove any skin oil first ) with a paste of MnO2 / finely -ground activaterd carbon.

                                                      The two electrode pastes, one with charcoal and the other with activated carbon; both with MnO2 recovered from a  lantern 1.5V. Zn/ carbon cell.

I use some 25% gum arabic (aq.) as binder; it forms a beautiful paint.

       A rectangular hot-plate ( hair straightener ) which sells the unit's plastic bag holder.  5-7 second applications of heat. Do not touch the super cap with the heat source!

                                                 "Peanut" resting at home with me!

   The above experiment reminds us of the great Michael Faraday who fate rescued from a life of abject poverty.  A young (or old) mind can develop with these simple devices. The young mind has an increased chance of , someday, using multi- million dollar instrumentation.


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!

Sunday, August 20, 2023

Inexpensive Activated Carbon/ Graphite Electrodes Poster Board ?

 Poster board painted with "Liquitex" varnish and dried in fume hood 3 hours. Lightly brush on a small amount of mineral oil and then apply well mixed epoxy resin. Pour fine -mesh activated carbon/ graphite on both sides over a pan. Lightly press. leave 24 hrs.  Aplpy a six-ton press.  Light mass/ wide surface area. Not flexible but there are applications like "air batteries". We will see....

See Below:

Note:  I did not like the measured resistance I observed for this approach.   It looks nice , but not useful.

However:  try deforming styrofoam cups in ethyl acetate solvent.  It forms a viscous paste and you can dilute it as needed.  I added graphite and finely screened activated carbon. Apply with brush to surfaces including poster board. Let dry 24 hrs. Resistance varies but does conduct!  Is it copper? No, but has potential use. Experiment with the application of the paste. I saw some low ranges of 200k ohm with a multi-meter at varying electrode distances.  Much safer than using acetone , in my opinion.