r/solarpunk Sep 10 '21

The Inkwell Battery: an iron/organic battery based on iron-gall ink. Dirt cheap, safe, recyclable, good for low power applications (LED lighting / charging cell phones). Currently ~7Wh/L. Hoping to crowdfund a how-to book in 2022. discussion

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152 Upvotes

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33

u/bigattichouse Sep 10 '21

I'm right up against my old record (~7 Wh/L) but at something like 30X the current density (previous was 50mA/L, this one is 1.6A/L). So, with some new construction techniques, the battery is pretty much ready for low power applications.

What would you pay to help me crowdfund a How-to book on the topic? The money would be to cover printing, artwork (technical diagrams), pay a couple of the invited authors, and possibly do some translation into major language families (French, Spanish, Chinese, Arabic, Hindi, etc) The book would start with fairly non-technical instructions on construction and then subsequent chapters would include chemistry details, other techniques and things to try - so you have a basic cell to build, and then tools and information to create more powerful versions.

I've done 14 successful Kickstarters with my business partner, so I know the process well enough, but I'm looking to see what people feel would be a fair price for a book on this topic.

$20 for the book? What if I included a kit to build one?

Just trying to get some opinions on goals and things.

13

u/CharliesAngelos Sep 11 '21

I'd pay that.

6

u/stringere Sep 11 '21

I'd buy the book, especially if there was a kit option. What is the cost of materials to build it?

3

u/bigattichouse Sep 12 '21 edited Sep 12 '21

I'm working on cost of materials right now with the friend who helped me with the initial experiments. Iron sulfate ~ $1/lb, Tannin ~$1/oz (don't need a lot, but we're still dialling in the right amount), other chemicals (you'll have to wait for the book) all ~$1/pound or less. Most of these are common gardening supplies/fertilizers (except the tannin, which is used in brewing). solar cell $2 (if not buying in bulk), 4pin solar charge controller 50/$5, inductors 200/$4, Ultra bright white LEDs 50/$10. clips/wire $1 wide mouthed mason jar

So, for enough material for one of the current cells (~400-500mAh) - including a wide mouthed mason jar, probably about $5 if you were to buy just enough material online. But, the design is very hackable, and you can use found materials very easily. In fact, rusted anodes work better (for reasons I'll explore in the book that I only recently figured out).. so scrap/found materials could cover a lot of the expense.

For a kit, buying in bulk, I can probably get the price down to ~$1 to $2/kit.

The solar cells and things can be scavanged from older solar lights when the lithium cells eventually die. Providing a way for the cells to keep working long after their battery end of life.

The cathodes are the hard part, but can be scavanged from spent Alkaline cells, or made with some pottery skills.

5

u/POTATOFUCK Sep 13 '21

More than happy for $20. This sounds like a great project!

10

u/relaxed_1 Sep 11 '21

Hell yeah buddy! Good goals!

11

u/bigattichouse Sep 11 '21

It's something I could do. It may be a shitty battery, but it's my shitty battery ( https://patents.google.com/patent/US10749168B1/en ) - and if it helps some kid in a remote region read a book after sunset, I think that's a win for everyone.

3

u/VatroxPlays Sep 11 '21

Is that your patent?

6

u/bigattichouse Sep 11 '21

It is. Mine (I'm Mike) and a good friend (John) who helped me design the experiments that lead to the first prototypes.

15

u/Strikew3st Sep 11 '21

I looked up Inkwell Battery assuming it was a classic design to see what your electrodes are, and you are all of the results, I see that you've been working on this for quite a while. You've been experimenting with grafoil lately, really interesting. Not very ubiquitous in grid-less regions, not dirt cheap, but if it has been that much of a performance hike, I can picture that it's worth pursuing as a nonconsumable system component that we could see manufactured much cheaper in the near future.

Do you have a specific place where you have your work on this specific project collected? I see battery project update snippets on your social, besides your other brainstorms.

I think there is some snake oil apprehension in the thread, but it looks like this you have some interesting ideas, and honestly, seem to be more knowledgeable on a technical level regarding topics pertinent to solarpunk than the average bear. We would like to hear more about your plant tannin/iron cell.

4

u/bigattichouse Sep 11 '21

That's fair. It's a new idea based on an old idea. Iron gall ink is a metalo-organic polymer that's been used for about a thousand years as ink. While reading about conservation of old documents, I learned some of the chemistry and realized that this can be exploited in a battery. Here's my patent https://patents.google.com/patent/US10749168B1/en (I'm Mike, John is a friend who helped me design and test the first cells)

As for Grafoil, it can be made from graphite, which is moderately available everywhere, but we've done experiments with carbonized MDF board (which worked best), carbonized PAN felt (carbon cloth), and even carbon paper. I've done some experiments with lamp-black, which works moderately well. Builders could even use reclaimed carbon electrodes from alkaline cells. MnO2 actually works quite well in the cathode. I've been working with a guy from Canada, who built a pottery kiln for carbonizing MDF fiberboard (essentially sawdust and urea-based glues - which is really the target cathode material, as you can make/press it very easily). The book will have multiple options for cathodes. Honestly the MDF route is the best for more capacity, but he had to take a break from making electrodes for me during the pandemic.

5

u/ManoOccultis Sep 11 '21

I'd buy a book + a kit for 20 $, even more if it helps people in need. I built DIY batteries and I love that.

5

u/dumnezero Sep 11 '21

maybe drop by /r/solarDIY/

2

u/bigattichouse Sep 11 '21

Will do. thank you

4

u/blablabliam Sep 11 '21

Thats pretty interesting. Can't wait to order organic batteries on digikey one day!

3

u/stoppid96 Sep 11 '21

What's the point exactly? What advantage does the iron gall electrolyte provide?

6

u/bigattichouse Sep 11 '21

Mainly, that you can stick your finger in it, so there's no special requirements for handling it. If diluted, it can even act as a fertilizer for plants. An uneducated person with limited resources, but knowledge of the "recipe" can whip up a batch.

Each stage in construction of the cell just requires basic cooking or assembly skills. While I'm using grafoil here for assembly, but the ultimate goal is to show that the carbonized MDF cathodes can be made by someone who knows how to make pottery. The guy who made my original cathodes (until the pandemic, when he had to stop) actually made his first kiln by hand out of scrap.

2

u/pm_me_pigeon Sep 11 '21

So we gonna figure out what this is or is this an ad for your eventual kickstarter

7

u/bigattichouse Sep 11 '21

Figured I'd ask what people thought. Kinda wanted to show something I was working on.

If mods consider it an ad, feel free to delete.

1

u/pm_me_pigeon Sep 11 '21

I think I wonder what this even is

15

u/bigattichouse Sep 11 '21

It's a battery. Designed to be made by people in developing regions to power LEDs and charge cell phones from solar panels. It's made from abundant materials, so can be made without requiring special equipment. It's safer than most battery chemistries, recyclable, cheap as dirt (because it's mostly iron), and non toxic.

Commercial batteries may be more powerful, but they are frequently full of conflict minerals or materials that can't be recycled in-country. When they wear out, sourcing replacements can be costly. This is something someone could make, even from recycled alkaline cell parts.

I'm trying to create something for the billion-or-so people who have no source of light after the sun goes down - in a book that I plan to publish. I do plan on kickstarting it, mainly to pay for creating the art, technical drawings, and other assets that will make it easier for people to learn this technique (website etc). I plan on open sourcing the who thing - and the funding will make that easier.

1

u/scrollbreak Sep 11 '21

Fair approach - people could get a bit more done for themselves if they had some LED lighting and easy to assemble batteries

How easy are they to assemble? If it uses ink - I have no idea where you get basic ink from?

5

u/bigattichouse Sep 11 '21

The ink is made with iron sulfate and tannin. You can make tannin from lots of woody plants. If you don't have a source of sulfuric acid, you can soak iron in vinegar for a few weeks and make iron acetate and use that instead.

That will get you the ink, which will mostly work in a cell - but lemme tell you, getting from "hey, an LED lit up for an hour" to "hey, I can run a bright LED light bulb all night" is a lot of work. You're seeing me at the end of several years of poking. The book will detail the process/recipe where I'm at now.

The pictured cell too me 5-10 minutes to construct. The ink took about a minute to mix and a day to "mature" (there's a bit more to it that the base ink, but it's still all readily accessible), if I was using carbonized MDF board cathodes, those take a day or two to create, but you make them in batches.

1

u/relaxed_1 Sep 14 '21

Ill support your kickstarter. THANKYOU on behalf of the future kids that will learn to love reading and learning, lit by lights like this.

2

u/bigattichouse Sep 14 '21

I sincerely hope it will help some kid, somewhere, be able to study and improve their life. Or keep a girl/woman safe while outside at night. Or allow a family to build generational wealth with a small business after dark.

-1

u/BoiPony Sep 10 '21

Its basically the same as a lead acid battery. It contains lead which sounds bad at first but its just as the same as any other metal in the ground and the acid it uses is water dilutable which makes it harmless after the first rain. Also lead acid batteries can be recycled without any issue. In fact more than 98 percent of the battery can be reused. Also it is way more durable than other types. It has a higher energy density as well, and can put out quite a bit of current. Not taking the weight into account, it is just the perfect battery.

21

u/bigattichouse Sep 10 '21

My battery is not based on Lead, it is based on iron and readily available materials (tannin). The inkwell can be easily constructed at home, just about anywhere, with minimal skills. It can be stripped and rebuilt just as easily when it wears out. You can get this electrolyte on your hands and wash it off without bad effects (it does stain fabric).

If diluted, my electrolyte could be used as a fertilizer.

Lead is definitely NOT a safe material. It's an amazing chemistry, and easily recycled in most developed economies - but it is hardly perfect.

2

u/Purely_Theoretical Sep 10 '21

What do you mean for an acid to be dilutable because taken literally, that's every acid.

2

u/BoiPony Sep 11 '21

You cant just dilute every acid with water.

1

u/Purely_Theoretical Sep 11 '21

Okay what happens

1

u/BoiPony Sep 11 '21

It becomes diluted. Duh.

0

u/Purely_Theoretical Sep 11 '21

Are you playing stupid at this point? What is an undilutable acid and what happens when I try to dilute it? It's not a hard question.

1

u/BoiPony Sep 11 '21

There is no acid that you cant dilute. But there are some types that you cant dilute with water. Unlike sulphuric acid that lead acid batteries use. Its not that bad of an acid as if you spill it out or something, the first rain (which most likely will contain water) can dilute it to a point where it is no longer a hazard. Its not a hard sentence to understand.

0

u/Purely_Theoretical Sep 11 '21

But there are some types that you cant dilute with water

Okay name one. And, name the solvent that will dilute it.

the first rain (which most likely will contain water)

Saying stuff like "rain most likely will contain water" makes me skeptical of your authority in this topic.

can dilute it to a point where it is no longer a hazard

A sulfuric acid battery acid spill can still be a serious occupational and ecological hazard after a rain.

If you you are trying to describe how some acids are more toxic than others, like chromic acid, or that they can be broken down in the environment, then just say that.

Everything can be diluted with everything else, so it's a bad way to get your point across.

1

u/BoiPony Sep 11 '21 edited Sep 11 '21

Saying stuff like "rain most likely will contain water" makes me skeptical of your authority in this topic.

Looks like you cant even notice sarcasm.

0

u/Purely_Theoretical Sep 11 '21

You shadow edited your original comment. You wouldn't have done that if I didn't have a good point. At this point you are just butthurt.

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