Revision as of 13:37, 9 November 2009

20.109(F09): Laboratory Fundamentals of Biological Engineering

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Battery Assembly

Measure the mass of powder and add to a clean agate mortar, determine the mass of Super P and PTFE to add based on this mass.
Measure out Super P and add to mortar. Do not add PTFE yet!
Grind thoroughly with mortar and pestle for about 15 minutes.
Add PTFE and mix together, use the pestle to press the mixture into a flat sheet that is all one piece.
Transfer to a stainless steel plate and roll out the electrode to form a uniform electrode.
Once rolled, transfer to the stainless steel cutting plate and use a circle cutter to make an electrode.
Measure mass of electrode and determine the theoretical capacity of the electrode. Co3O4 has a theoretical capacity of ~890mAh/g, FePO4•H2O has a capacity of 143 mAh/g (milli Amp hours per gram).

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 ==Protocols==
-All material should be isolated and dried to form a powder. This powder is what will be used to make the battery electrodes.  In all battery electrodes there is a certain percentage of active material, a small amount of conducting material and a small amount of binding material. In these batteries, the conducting material will be a particular type of graphite carbon called “Super P”. The binder is a compound that causes all the powder to stick together and form a flexible film, the binder is teflon (poly(tetrafluoroethylene)—PTFE). These will be mixed at a ratio of 70% active material, 25% Super P, and 5% PTFE.
 #Measure the mass of powder and add to a clean agate mortar, determine the mass of Super P and PTFE to add based on this mass.
 #Measure out Super P and add to mortar. Do not add PTFE yet!