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Potassium Sulfur Silica Battery

In the future lithium reserves may not be as easy to mine as they are today, Potassium could be an alternate alkaline metal for batteries.

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Lithium reserves are like any other natural resource, they could be much larger than currently thought or they may run low making lithium batteries cost prohibitive. Potassium however is extremely abundant and easy to mine making it an attractive alkaline earth metal for batteries and in some ways a better option.

The stokes radius of dissolved potassium ions is actually smaller than the lithium ion allowing it higher mobility in an electrolyte and in the electrodes of a battery. This will allow faster charging and higher C rates for high power applications (cars).

Potassium Sulfide is also very easy to synthesize and can be combined in-situ with a conductive carbon matrix making it a great candidate for a potassium sulfur silicon/silica battery with a much higher energy density than todays lithium ion batteries. Potassium is also very stable (lower overpotential required for charging than lithium) providing a much higher cycle life in batteries.

One of the major problems we face in wide adoption of electric vehicles and grid storage systems is cost. I am fixing that, and providing better batteries at the same time.

Making potassium sulfide is easy to do, all that is necessary is to heat potassium sulfate or K2SO4 with carbon and K2S and CO/CO2 are evolved. This can be completely carbon neutral in the case of using an activated carbon from coconuts.

The plan is to simply dissolve the K2SO4 in distilled water then add it to an excess of pulverized activated carbon. Dry the mixture so as to precipitate the K2SO4 in the pores of the activated carbon and then heat it in a crucible till the reaction is complete. At this time the pores of the AC will be full of K2S and can be simply combined with graphene/carbon black and assembled in a cell as the cathode.

The same exact anode as the lithium sulfur silica battery will be used. Amorphous silica is the best bet for high energy storage and food grade diatomaceous earth fits that bill perfectly. It is incredibly cheap compared to synthsized silica and has a morphology better than nano-silica being that it is highly porous and possesses a huge surface area.

A modified DMSO KOH KNO3 Diatomaceous Earth (crystalline) and Graphene Oxide electrolyte seperator will be used. This should give conductivity close to 10^-3 sieverts per cm.

This is even more advantageous as the electrolyte is much cheaper than an equivalent for lithium.

The performance will be lower than lithium sulfur silica but should still achieve over 800 mAh per gram at 2.2 volts per cell.

This documentation describes Open Hardware and is licensed under the CERN OHL v. 1.2. You may redistribute and modify this documentation under the terms of the CERN OHL v.1.2. (http://ohwr.org/cernohl). This documentation is distributed WITHOUT ANY EXPRESS OR IMPLIED WARRANTY, INCLUDING OF MERCHANTABILITY, SATISFACTORY QUALITY AND FITNESS FOR A PARTICULAR PURPOSE. Please see the CERN OHL v.1.2 for applicable conditions

  • 1 × Activated Carbon, milled to 300 mesh or finer powder
  • 1 × Potassium Sulfate
  • 1 × Crucible
  • 1 × Propane Torch
  • 1 × Refractory forge

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  • Fire Proof Wood

    MECHANICUS03/30/2016 at 12:37 0 comments

    And fire proof batteries.

  • Pre Potassiation of Anode Easier Than Once Thought.

    MECHANICUS03/29/2016 at 03:57 0 comments

    Thats a word I created it.

    THE ANODE!!

    KOH 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 K2SiO3 or K2O•nSiO2

    The balanced equation is as such n SiO2 + 2 KOH → K2O•nSiO2 + H2O from wikipedia.

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

    The K2SiO3 is soluble in water hence the need for an excess of SiO2, this is boiled to dryness and the soluble K2SiO3 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 Li2SiO3 for which there is no wiki page.

    THE CATHODE!!

    I heated the dried K2SO4 today in a crucible with the activated carbon to synthesize the K2S. 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 K2S. At this point however neither the anode or cathode can come into contact with water as they are reactive and soluble with such.

    ELECTROLYTE!!

    KNO3 in THF and emulsifier??? I have no idea yet, more later.



  • The basis for my strategy

    MECHANICUS03/22/2016 at 13:10 0 comments

    http://pubs.acs.org/doi/abs/10.1021/ic500919e

    This paper entails the opposite of what I am attempting.

    I will start with a potassiated cathode so the full cell will be discharged upon assembly, this should increase total amp hours per gram as there will be a perfect amount of sulfur compared to potassium in the cathode.

    A slight excess of amorphous silica in the anode will give the potassium ions plenty of space to fully intercalate, this is going to be awesome!

  • Potassium Sulfate has Arrived

    MECHANICUS03/21/2016 at 23:35 0 comments

    All my materials are here, I just spent a few hours reading about lithium sulfate aqueous electrolytes in AC/AC symmetric super-capacitors. With the addition of potassium iodide they can actually perform as well as exotic organic electrolytes in EDLC super-capacitors.(in energy density not voltage potential)

    This is significant as if the K+ cation conductivity is high enough in the neutral aqueous electrolytes they are almost perfect for potassium sulfur batteries. The benefit being poly-sulfides are insoluble in water which will keep them in the cathode where they belong and solve the issues that have plagued lithium sulfur batteries for so long. As the poly sulfides migrate to the anode they cause irreversible capacity fade.

    The problem with aqueous electrolytes is that they are limited to around 1.2 volts per cell when they are highly basic or acidic, (exception is lead acid) however being that potassium sulfate or lithium sulfate is pH neutral the cells can operate up to 1.9 volts. Potassium Sulfur batteries are limited to 2.2 volts anyway with any noticeable capacity starting at around 1.9 volts.

    One noticable problem is that K2S in the presence of water will form a lewis acid and KOH will be evolved however basic aqueous electrolyte at the cathode does not cause a problem, the evolution of oxygen at the anode is really what limits most aqueous electrolytes to around 1.2 volts.

    The first step however is to synthesize potassium sulfide using activated carbon to absorb a saturated solution of potassium sulfate and water then drying in the vacuum oven. This will allow all potassium sulfide evolved from heating to be kept deeply in the pores of the activated carbon increasing conductivity between the insulating sulfur that will evolve upon charging and the carbon backbone that conducts electrons.

    This will then be placed in a crucible and heated with a propane torch for 30 minutes. Carbon monoxide and carbon dioxide will evolve so this should be done outside.

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Morning.Star wrote 12/20/2017 at 05:03 point

Hi Mechanicus.

May I ask where you got the inspiration for this cell? Several years ago I made a 'cell' accidentally and have been trying to figure out the chemistry ever since.

I've never seen crystal silicon in a battery, nowhere except semiconductors before, although I have used carbon a fair bit in my experiments.

I'm looking at your list of ingredients and thinking, most of that is probably in the flue sealant I used to create the cathode on mine.

I never made a project out of this because the materials are very hard to duplicate outside of the UK and I have a feeling its something I'll never be able to resolve due to trade secrets - I'll never know the exact chemistry. It is a shame, but thats how it goes.


Did you ever manage to get it to work? :-)

https://hackaday.io/page/3067-quantum-electron-tunneling-revisited

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Scott Phillips wrote 03/28/2016 at 19:55 point

Just started an account specifically to say: this sounds *excellent*. Good luck for the 2016HACKADAYPRIZE!

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MECHANICUS wrote 03/29/2016 at 03:10 point

Gratitude.

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