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There are 99% more failures than success when developing new technology. This has been no exception to the rule although when I first stepped down this path I thought differently.
Many things were wrong. I had to go back to the drawing board almost completely.
I need Si not SiO2 for Lithium to bond to in the anode, ball milling with aluminum and then heating to 350 degrees celcius should allow a reduction of silica to silicon.
http://scitation.aip.org/content/aip/journal/jap/80/11/10.1063/1.363669
This paper describes the failure of diodes made with Al SiO2 Si do to high temperature.
Going forward I need a few more materials to make these things work as they should.
I should receive some commercial poly-propylene semi permeable lithium ion battery seperator in the mail anyday from china.
The electrolyte is the most debated section of these batteries in the literature. I have attempted solid electrolytes this past week using PMMA to no success.
It seems going forward a liquid electrolyte will be the simplest way to demonstrate viability. Ultimately a solid sol-gel PEO electrolyte will be necessary but I need quite a bit of more equipment before I can process PEO.
1.0 Molar lithium b(TFMS) the standard in academia for electrolytes and prelithiation of the anode, costs around 60 dollars for 10 grams and should be immediately ruled out for commercial applications due to cost. This leaves me with using lithium perchlorate for pre lithiation of the anode and for the 1 molar solution in the electrolyte.
Using LiOH in the electrolyte was folly as it doesn't solvate well in PEG 400 but that was not indicated in any resource I could find.
Also using PEG 400 solely for the electrolyte will not work, instead I will probably be using a mixture of Tetrahydrofuran (THF) 1000Ml Composite Bottle Reagent Grade, 1,3-Dioxolane, =>98.0%, stabilized, Synthesis Reagent, 25mL, 1,2-Dimethoxyethane, =>99.0%, Analytical Reagent, 30mL. And for the lithium in the electrolyte .1 molar lithium nitrate, and 1 molar lithium perchlorate.
Pre lithiation can be achieved with lithium salts and silicon in a ball mill using hexane as a lubricant???? http://pubs.acs.org/doi/abs/10.1021/ic501923s I love staring at abstracts trying to make sense of things, I am hoping they didn't use Li b(TFMS) in this study and used something more like lithium perchlorate. It's worth a shot and I am going to try it as a step in between the, hydrothermal reduction of silicon dioxide and oxidized nano carbons into silicon carbide, and the final step of blending with the binder and applying to the charge carrier.
I am starting to question if this is wholly feasible, I am on the edge of buying a 15% by weight igMWCNT to 85% PA 6/6 masterbatch from cheaptubes.com I know for a fact it will probably be too brittle but combining something more akin to 6% igMWCNT and 3% reduced graphene oxide would probably work better and retain more of pristine PA6/6's mechanical properties. However, cheaptubes really means cheap tubes and nothing else all their graphene is synthesized and is incredibly expensive. The resistivity of the 15% master batch is spot on with what I need for this to work at 2 ohms per cm. Mike at cheap tubes hasn't gotten back to me yet on the physical characteristics of these masterbatches. There is always the option of twisting these up warm, but I just don't have any of that figured out yet, this will work in some form or fashion it is not obvious, however.
Work continues on designing a water cooling system by 3d printing molds for molds I will have more on this later as I have already release too many defunct mold models.
http://www.sciencedirect.com/science/article/pii/S037877531301999X
Polysulfide shuttle control: Towards a lithium-sulfur battery with superior capacity performance up to 1000 cycles by matching the sulfur/electrolyte loading
Xin-Bing Cheng,Jia-Qi Huang,Hong-Jie Peng,Jing-Qi Nie,Xin-Yan Liu,Qiang Zhang,Fei Wei
Journal of Power Sources
Elsevier
1 May 2014
Copyright © 2013 Elsevier B.V. All rights reserved.
http://www.sciencedirect.com/science/article/pii/S0378775314018035
Manganese modified zeolite silicalite-1 as polysulphide sorbent in lithium sulphur batteries
Vida Lapornik,Natasa Novak Tusar,Alenka Ristic,Rajesh Kumar Chellappan,Dominique Foix,Rémi Dedryvère,Miran Gaberscek,Robert Dominko
Journal of Power Sources
Elsevier
15 January 2015
http://pubs.acs.org/doi/abs/10.1021/nn507178a
"Lithium–sulfur batteries hold great promise for serving as next generation high energy density batteries. However, the shuttle of polysulfide induces rapid capacity degradation and poor cycling stability of lithium–sulfur cells. Herein, we proposed a unique lithium–sulfur battery configuration with an ultrathin graphene oxide (GO) membrane for high stability. The oxygen electronegative atoms modified GO into a polar plane, and the carboxyl groups acted as ion-hopping sites of positively charged species (Li+) and rejected the transportation of negatively charged species (Sn2–) due to the electrostatic interactions. Such electrostatic repulsion and physical inhibition largely decreased the transference of polysulfides across the GO membrane in the lithium–sulfur system. Consequently, the GO membrane with highly tunable functionalization properties, high mechanical strength, low electric conductivity, and facile fabrication procedure is an effective permselective separator system in lithium–sulfur batteries."
Permselective Graphene Oxide Membrane for Highly Stable and Anti-Self-Discharge Lithium–Sulfur Batteries
Jia-Qi Huang†, Ting-Zhou Zhuang†, Qiang Zhang*†, Hong-Jie Peng†, Cheng-Meng Chen‡, and Fei Wei†
† Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
‡ Key Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
ACS Nano, 2015, 9 (3), pp 3002–3011
DOI: 10.1021/nn507178a
Publication Date (Web): February 18, 2015
Copyright © 2015 American Chemical Society
Reprinted with permission from {Permselective Graphene Oxide Membrane for Highly Stable and Anti-Self-Discharge Lithium–Sulfur Batteries}. Copyright {2015} American Chemical Society.
A Lithium Ion, Sulfur-Cathode, Silicon Anode battery has not been tried yet. The question is why has this not been tried? Silicon-Lithium batteries are made with nano-silicon wires pre doped with lithium in the Anode. Sulfur Lithium batteries are made with a Solid Lithium Anode and a Sulfur Cathode. Combining the two should allow a greater increase in performance.
Lithium-Sulfur batteries have a theoretical energy density of 2200mAh per gram, Lithium-Silicon batteries also have a theoretical energy density of 4200mAh per gram. Super Capacitors have an theoretical energy density of 200-400mWh per gram.
The idea now is to combine all three and reduce the lithium required to make the Ultra-capacitor by half of that of a normal battery.
In order to create the Anode a very high loading of Urea will be required to fully reduce the Kieselguhr (amorphous Silicon Dioxide SiO2) GO, oxIMWCNT and lithium hydroxide. Kieselguhr should provide a benefit over SiO2 nanowires in that its total surface are should be much higher. The benefit should remove the need for a binder as the anode will be highly cross linked. MnO2 addition will increase the lithium ion storage capability of the small amount of Carbon needed to facilitate electron flow to and from the reduced SiO2[1}. This electrode will be spun cast onto a stainless electrode and reduced in-situ via microwave assisted urea reduction. I will harvest the lithium from an energizer battery and convert it to hydroxide by placing it in water.
A reduced Graphene Oxide, oxiMWCNT secondary Anode will protect the Primary Silicon Anode from sulfating significantly increasing the lifespan[2]. This should also provide a layer that will demonstrate Psuedo-capacitance with a phosphoric acid/lithium ion electrolyte. A dodecylbenzene sulfonic acid seperator will be applied to the interspacial area between the secondary anode and the cathode, this will allow the psuedocapacitive double layer to avoid leakage while remaining permable to ion flow under normal conditions this has also not been tried. Ideally the psuedocapacitive effect should have the least resistance and discharge/charge first allowing surge power and surge charging to happen almost instantaneously. A crosslinked solid PVA borax electrolyte should provide enough support to keep the secondary anode from degrading do to ion swell during charging. The amount of borax needed is a large variable and will require much experimentation. This electrode will be drop cast upon glass containing an aluminum mesh screen, then reduced in-situ via microwave assisted urea reduction.
The cathode will be constructed with a majority of Asphaltenes as the 7% sulfur and 3% nitrogen loading as well as vanadium and nickel hemes will allow a large amount of lithium to be adsorbed upon discharge of the cell and will facilitate faster charge/discharge rates{3,6}. A small amount of partially reduced N Ox MWCNT will allow higher conductivity on the Cathode. A binder in the form of Chitosan will be required due to the small amount of reduction and subsequent cross linking of the Cathode. The chitosan will also sufficiently retain the sulfur in the cathode reducing the significant wear rate from sulfur migration seen in as to date lithium-sulfur batteries. This electrode will be partially solvated and dispersed in household vinegar drop then drop cast onto a stainless steel charge carrier. It will then be reduced via urea microwave assisted reduction in-situ
Ideally the electrolyte should be an ionic liquid to allow higher super, constructed with quaternary ammonium salts. However I have tried unsuccessfully to create one with cheap readily available materials, as the urea used to form the deep eutectic solvent degrades upon...
Read more »Pretty much all my updates will be on youtube from now on, I have made some new fibers and will get them up asap I had about 40 more problems since the last update but we are cruising back into territory I know my way around in the field of chemistry.
I had to rebuild my 3d printer it is a prusa I3 rework from ebay. I needed risers and a hopper printed for my filament extruder and what I had was just not cutting it. There were many broken parts as it was shipped rather haphazardly. It is rebuilt now and all axis are tight and moving.
I am looking at building a website to better host this information as there are alot of steps past getting the actual large production tools built, but I have tested all of this on a small scale and it works. If anyone has any idea as to the best place for free web hosting let me know.
I completed most of the extruder today, I simply need a 5/8 spade bit to finish it. Will complete tommorow, Still working on completing the first 3d printable end connector prototype in design spark mechanical. Picture is up.
My previous connectors were made with clay and molded with silicone and high temp resin, they looked like hell but were simply usefull to prove to myself this would work.
If you haven't used design spark you definitely need to check it out. http://www.rs-online.com/designspark/electronics/eng/page/mechanical its a free super simple cad program that is perfect for designing 3d printable objects.
So you have recieved some cheap 90% clean multi walled carbon nanotubes. That's great but they are pretty useless as is, the first order of business is to clean and functionalize them using nitric acid , 30% hydrogen peroxide and an ultrasonic cleaner.
Cover your work area with disposable materials that you can throw away, don long gloves, safety glasses, lab coat, covered toe boots and a respirator before cracking the container that contains the nanotubes. The respirator should be able to filter organics and fine particulates. It would be best to do this in a filtered fume hood but it is not necessary if you are careful and don't create alot of dust.
Add an amount usually 20 grams is what I use, to the tared mason jar.
Nitric acid is pretty benign but H2O2 can start fires very easily. Have a fire extinguisher on hand.
Add either conc. nitric acid and 30% H2O2 in a 50/50 by volume ratio or soley 30% H2O2 to the jar just covering the nanotubes. The nitrogen functionalized tubes will be used in the Cathode and the purely oxidized iMWCNT will be used in the primary and secondary Anode. Place the stick blender in the Jar and place the jar into the ultrasonic bath. Start the bath and begin blending on high, blend for 30 seconds every 5 minutes and sonicate for 60 minutes total.
The nitric acid will fume and you definitely don't want to breathe it so wear the respirator that filters organics. DONT DO THIS IN YOUR HOUSE. The H202 will also release oxygen gas so have no flames present.
After 60 minutes of continuous sonication and blending you are ready to filter the iMWCNT. Attach a Buchner funnel to a filter flask and place a whatmann number 1 filter paper in the Buchner. Attach the vacuum line to your filter flask and turn the pump on. Wet the filter paper down so it forms a seal with the buchner and is pushed down by atmosphere.
See my how to filter video here. I had trouble removing excess nitric from these iMWCNT so I ball milled them with distilled water overnight, other than that the procedure is the same your vessel will be the reaction vessel instead of the ball mill.
Slowly pour the foamy functionalized iMWCNT into the funnel and rinse with distilled water untill the PH of the effluent is nuetral. It will often take about a full gallon to rinse 20g of fiMWCNT.
Allow the vacuum to be continually pulled once f-iMWCNT have been rinsed, this will assist in drying the filter cake.
Dump the filter cake after drying for a few minutes onto a tared aluminum raft, scrape down the sides of the Buchner funnel to remove as much of the solid as possible.
Place the aluminum raft into a drying oven and dry overnight at 175 degrees Celsius and 25 inches of vacuum. When drying is complete weigh the raft with f-iMWCNT to determine losses due to amorphous carbon and iron being removed from the as bought i-MWCNT. When using only 30% H2O2 to functionalize there will be less losses due to the iron and amorphous carbon still present.
Record all weights in your lab notebook.
Follow all lab safety procedure.
Follow the above procedure substituting 75 mesh ultra fine graphite for the iMWCNT.
Follow all lab safety procedure.
Place 20 grams of dried asphaltenes into a tared flask, record the weight. Add 300-400 mL of acetone to the jar.
Place a stick blender into the jar and place the jar into the ultrasonic bath, blend and sonicate as above for 30 minutes. The mixture will get very warm, be sure not to have any ignition sources nearby as warm acetone is very flammable, always have a oil rated fire extinguisher within reach.
Following the above procedure in step 1 filter the asphaltenes and wash with acetone.
Place the wet asphaltenes onto a tared aluminum raft and place into your vacuum oven. Dry at 80 degrees Celsius and 25 inches of mercury for 1 hour.
Record the weight of the washed asphaltenes and raft. Calculate losses and record in your lab notebook.
Yah the fishing line was rudimentary at best, I expect Dallas nanotech is going this direction as well, I wanted to get it out there open source so they can't patent the next evolution of it. I have some other very interesting projects I am working in relation to this but I am not reavealing them untill I have these muscles fully developed.
The link on the left is the original scientific journal publication. Do a google search as well. They are not very useful in those situations as they need better thermal properties.
i would be very interested in looking into these ideas, do you know more or can you post some information about the science around the filaments?
MECHANICUS
Wasim Sahu
CriptasticHacker
Theresa
Wow, artificial muscles project was on my bucket list too!
There was a YouTube video some times ago, with a guy heating fishing wires with a hair dryer. Since then, I started thinking how this idea can be "twisted" even more. Never related it with ultra-capacitors, thought.
Your project really sparkled my interest, well done!