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Explore Community Submit All Art Craft Food Games Green Home Kids Life Music Offbeat Outdoors Pets Ride Science Sports Tech Building a "Baghdad Battery" by IanW on October 31, 2008 Table of Contents intro: Building a "Baghdad Battery" . 2 step 1: Construction Overview an Materials . 3 step 2: Making Fe3O4 for the Iron Electrode . 3 step 3: Constructing the Electrode Pairs . 4 step 4: Containment of Electrochemical Cells an Other Notes . 6 step 5: Monitoring Performance of Cells . 9 step 6: Performance of this "Baghdad Battery" replica . 11 step 7: How this 'replica' differs from other attempts . 14 step 8: Interpretation of the Artifacts . 17 step 9: History . 18 step 10: On other published accounts . 19 Related Instructables . 21 Advertisements . 21 Customized Instructable T-shirts . 21 Comments . 21 http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ intro: Building a "Baghdad Battery" The intent of this instructable is to provide ideas for experimenting with battery chemistry in general, and to summarize my experience producing a replica of what is often referred to as the Baghdad Battery. In my version of a replica I argue the artifacts have been misinterpreted in replicas previously built by other investigators. The replica I've created yields not only a better performing cell (capable of 5x the capacity), but one that is rechargeable. This is not a great cell, and our cars and homes will likely never employ the design, but it is curious that ~2000 years ago people may have been experimenting with electricity. What they were using this electricity for is subject to as much speculation as the actual construction of the "battery" (Perhaps it was not a battery, that is for you to decide). To keep the interest of the reader and focus on the construction aspects of the replica I will try not to write too much about the history and interpretation by others of the artifacts. Several of the sources listed in Step 10 have already done a wonderful job discussing these details. A few notes: >Several of the listed artifact photos were found on Wikipedia or widely used on the web, so I am assuming there are no copyright infringements. >Since this is my first instructable, and it has been a while since I've had to explain anything to someone through writing, I welcome all criticism and suggestions for improvement. >I would like to reference photos and figures inline with the text since I presume it would be easier for the reader to follow, but I am unsure if there is a way to do this through the instructable editor interface and wiki markup (?) - so for now I am just listing relevant images at the bottom of a step. Also, I'm unsure how to apply subscripts in the editor to write chemical formulas, I'd like to include the half cell reactions - otherwise I can take a screenshot and post it as an image. Image Notes 1. asphalt seal 2. copper sheet cylinder 3. iron rod http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ step 1: Construction Overview an Materials Based on an assimilation of the various sources listed in step 10 and several trials exercising possible permutations, the cell I settled on as being most likely is a Cu|Fe3O4 electrode pair immersed in KOH 20% that operates as a rechargeable battery - not a single use battery in which the electrodes are disabled by the reaction, as seen with an acid electrolyte. I think urine is just as likely to be the electrolyte, but I have some health problems and a diet that trends toward an acidic urine, so I was unable to test this. Plus my wife would likely take issue with urine sweating out of a porous jar on our kitchen table. Now that I think about it, she wasn't thrilled about the KOH either. I did not create a true replica, since I could not find a porous jar with the correct geometry. However, jar geometry should not have much effect on the battery performance. Also, a clear vessel - such as the mason jar I used - is helpful for observing the chemistry. If you want a replica that is similar in form to the artifacts, use an unglazed jar with the geometry seen in the photos, and substitute asphalt for the rubber tape I used as a sealant. Nothing is precise here, so feel free to substitute similar materials. For example, I used bundles of nails before I could find a large iron nail. Just be careful what you use is uncoated iron, many iron objects in the hardware store will be coated with a polymer or zinc (galvanized). Regardless of where you find the metals, ensure your copper and iron have the oxidation layers cleaned off - I used Al2O3 abrasive to clean the copper, and HCL acid for the iron. Materials: sheet of copper, it can be found in craft stores -copper pipe found in the hardware store will work too, but the slit seen in the side of the copper tube (in photos) does improve performance, so try to emulate this construction detail (use a saw or mill) piece of iron with an Fe3O4 coating - I used a large iron nail and created my own Fe3O4 coating, see step 2 for details on creating Fe3O4 mason jar or similar non reactive container for holding the electrolyte and electrodes - if you have a porous clay jar, try this instead stranded and solid wire rubber stopper rubber mastic tape, or if more adventurous, try asphalt rubber gloves an alkaline electrolyte - Potassium Hydroxide (KOH), also known as Potash, or an alkaline urine should work. Note: Be careful with retailers of KOH, since there is some paranoia of KOH in certain areas. My first attempt at purchase was a bad experience and waste of time. I believe the first company I contacted was under investigation for supplying methamphetamine manufacture - I'm not quite sure who the owner thought I was. Anyway, stay away from any companies that rhyme with "Spinner Chemical" and are based in Michigan. I won't advertise the company I did have success with, but if you can read the label in one of the photos, my experience was completely painless with this company. Image Notes Image Notes 1. don't use rebar - I tried - it is not pure iron, despite what the hardware store 1. this vase would have been perfect for a final replica (except it is glazed), but is guy might tell you an heirloom in my wife's Japanese family, an I would probably get in a lot of 2. rubber mastic, the duct tape of battery cell construction, wonderful stuff trouble if I used it, she caught me inspecting it 3. stranded an solid wire 4. iron nails, I used the large one to the left, but several of the small ones will work too - the bunch to the far right has a light coating of rust, but not enough to create a good layer of Fe3O4 5. wire strippers step 2: Making Fe3O4 for the Iron Electrode If your iron is already coated with Fe3O4 ('black rust'), you can skip this step. In the photos below, I show bailing wire, one possible option that comes coated with Fe3O4 and can be found in most hardware stores. The best option is to heat the iron until orange (temperature of decalescence 475 F to 525 F), either in a forge or with a torch, it will oxidise and leave behind Fe3O4. If you live near an ocean, leaving iron in seawater for an extended period should create a coating of Fe3O4. Or, you might scavenge for some Fe3O4 coated iron near the shorelines - I found some last time I was near the ocean. Since I am not near an ocean at the moment, don't know any blacksmiths, and wanted to speed up the process, I used the following recipe: First you will need to create Fe2O3 (red rust). If your iron already has a good coating of red rust, you may skip this part. If you need to make your own red rust, it is a little trickier since you will need to handle a few chemicals, but not bad. My recipe is not optimal, if you have Nitric acid and washing soda you can do better, but neither of these chemicals can be easily found at a hardware store - so, for most people, this recipe should be easier to implement. Near the concrete section of the hardware store, you will likely find something labeled as 'Muriatic Acid' - it is actually 30% HCL. Use your rubber gloves when handling any chemicals. Dip your iron nail in a mason jar of this acid and you will be left with a clean piece of iron ready to be oxidized. Now, pour another jar full of household Clorox bleach (or generic) and dip the cleaned iron into this solution. Allow the iron to dry in a glass dish - and you should have a nice coat of Fe2O3 (red rust). Now that we have a good coat of Fe2O3, we will convert this to Fe3O4. The Fe3O4 will appear as a black coating over the iron, where the red rust was formerly. Heat a pot of water on the stove until it is boiling and place the red rust coated piece of iron you created in the boiling water, after a few minutes it should turn http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ black, now you have Fe3O4. Image Notes Image Notes 1. a helical electrode I experimented with by wrapping around a chopstick 1.