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1200 mAh/g Lithium Sulfur Silica Battery

This is my Sistine Chapel, not because it's beautiful but because the time it has taken and it's paintable.

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I have toiled with this technology for a very long time now, it's become a love/hate relationship. However I am ready to crush my electrodes, see them charged before me, and to hear the lamentation of the brush-less motors.

There were a million things to learn, in regards to electrolytes, separators, charge collectors, sulfur solubility, electrode conductivity, electrolyte conductivity... etc.

So much I thought I needed elemental silicon to get these to work, but amorphous silica it turns out works just as well.

I am going off the beaten path here as everything I have learned is getting pretty much thrown out the window, so if you want sources or how I arrived at this destination check out last years attempts in my older project.

Then, prepare yourself for 1200 mWh per gram batteries, that cost 1/10th of current technology. And will be 3d printable at home with a small investment in the machine needed which will be yet another project.

The obstacles of progress are wide and tall but are fun to smash into and break.

The challenge isn't really a challenge unless you think the marine fighting the giant fire monster in the old commercials was just a challenge.

Wow, where to begin? I will start with the good news and move on to the unknown.

The Anode/Anolyte: Diatomaceous Earth (freshwater amorphous type)

Anode is prepared by reacting LiOH with SiO2 in water at 90 degrees Celsius. Then ball milled with Carbon Black and Graphene Oxide.

The next step is to add silver coated copper, to bring the resistance down to 2 ohms, this actually only requires around 2% by weight addition and is much lighter than using a hefty copper foil.

Along with the copper flake I add the electrolyte which is totally counter to everyway batteries are currently made but makes 100% more sense. If the electrolyte (anolyte in this case) is mixed in it has perfect contact with the electrode and no waste of mass or space occurs. The second reason for adding the solid gel electrolyte to the anode is that it can act as the binder material saving even more mass and volume.

PVDF, PVP, Lithium Perchlorate, and Lithium Nitrate make up the anolyte, which can be thinned with THF.

This is all done and bottled in a vacuum or blanketed with noble gas, and can be thinned to spray, pad print, screen print, roll, 3d print with drop casting, you name it.

The seperator/polysulfide screen: Graphene Oxide, Diatomaceous Earth (crystalline ancient type)

The main problem with Lithium Sulfur batteries is that the polysulfides of lithium have a tendency to migrate to the anode instead of reducing upon charging. This must be remedied so I utilize a anolyte that has low solubilty for polysulfides and more importantly create a small Gandalf that will allow lithium alone to pass. This works exceptionally well as not only do GO and DE stop poly sulfides they also enhance the conductivity of the solid gel polymer electrolyte. The electrolyte itself consists of PVA/PEG lithium perchlorate, and lithium nitrate, The PVA/PEG are very hyrophillic and are impossible to dry, however the water present does not react adversely with lithium ions but will completely stop lithium poly-sulfides in their tracks. Keeping the anode free of sulfur and the cycle life of the battery high.

The Cathode/Catholyte: Sulfur re-crystallized into mesoporous Activated Carbon, DMSO/Ca+Polysulfides

This is the area I am moving into now, another million combinations. Sulfur is highly soluble in DMSO at elevated temperature and sparingly soluble at room temp. This will be exploited to recrystallize the sulfur depositing it into the mesopores of activated carbon. Sulfur is entirely non-conductive like the silica so it needs lots of help. To assist carbon black and graphene oxide will be added. The GO will be slightly reduced leaving plenty of active sites for more lithium reactions. I may plasma etch and functionalize all the carbons in the cathode as well in order to increase lithium reactivity as sulfur can react with only half the lithium ions as silica.

When all this is prepared nickel flake and silver nanoparticles will be added to the mix, the nickle and silver make the sulfur reduction more favorable and can increase the voltage potential of the cell. Along with DMSO the cathode potential can be lowered even further hopefully eeking out 2.6 or 2.7 volts in the full cell configuration with the silica anode.

Lastly a solid polymer gel electrolyte consisting of PVDF, PVP, DMSO, Ca+Polysulfide and lithium nitrate will be added, the cathode can be thinned for painting with THF.

The concentrations of the cathode materials are unbeknownst to me but I have an idea I need to start with 80% sulfur. This leads to huge conductivity problems, however with the nickel flake and silver I am confident I can match the 2 ohms per cm resistance of the anode.

The application and building cells

The first cells will be constructed with simple stencils and airbrushing. Ultimately...

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  • 1 × Lithium Metal Foil
  • 1 × Lithium Sulfate
  • 1 × Lithium Perchlorate
  • 1 × Lithium Nitrate
  • 1 × Carbon Black

View all 22 components

  • LiSiOx

    MECHANICUS04/03/2016 at 06:23 0 comments
  • Fire Proof WoOd?

    MECHANICUS03/30/2016 at 12:38 0 comments

    And fire proof batteries.

  • Synthesis of L2SiO3 and L2S

    MECHANICUS03/29/2016 at 04:07 0 comments

    The synthesis of these two compounds is exactly as with potassium. NO PATENT INFRINGEMENT LOL TO THE BANK!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! :)^10

    THE ANODE!!

    LiOH and SiO2 in water heated to 90 degrees Celsius yields a water soluble compound.

    So today I performed these reactions with an excess of SiO2 to decorate the surface of the diatoms with Li2SiO3 or Li2O•nSiO2

    The balanced equation is as such n SiO2 + 2 LiOH → Li2O•nSiO2 + H2O from wikipedia. For potassium but is the exact same with lithium. (molar masses are different but more later when I get the right concentrations figured out.

    https://en.wikipedia.org/wiki/Potassium_silicate

    The Li2SiO3 is soluble in water hence the need for an excess of SiO2, this is boiled to dryness and the soluble Li2SiO3 will crystallize on the surface of the diatoms.

    The best news is it avoids all the patents :)^10

    Also I can use the exact same strategy to make K2SiO3 for which the wiki page is above.

    THE CATHODE!!

    I heated the dried Li2SO4 today in a crucible with the activated carbon to synthesize the Li2S. Both these materials need to be combined with carbons(graphene or carbon black)/metal powders to make them conductive. Also an excess mass molarity of sulfur needs to be combined with the Li2S. At this point however neither the anode or cathode can come into contact with water as they are reactive and soluble with such.

    ELECTROLYTE!!

    LiNO3 in THF and emulsifier??? I have no idea yet, more later.

    This is the exact same post as on the Potassium Sulfur Silica battery page lol.

View all 3 project logs

  • 1
    Step 1

    Dissolve Lithium Sulfate into distilled water to saturation

  • 2
    Step 2

    Combine saturated distilled water with ball milled Granular Activated Charcoal

  • 3
    Step 3

    Boil off distilled water.

View all 3 instructions

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