# Aluminum Battery with PAC setup : Rapid voltage drop problem after a charge

I am a retired man and seek for activity. I dont have background in chemistry but I want to learn an aluminum battery..the known problem is my aluminum metal get eaten and also corrosion even if using sodium electrolite and worse if using Aluminum chloride.

So I just try PAC for water treatment and it look like the reduction is minimum. But as usual the usual voltage drop always problem in any set up of galvanic.

What happen and how to prevent that? my experiment setup is a square aluminum that act as a case also as cathode. Fill with carbon powder separated by paper. in the center is a graphyte rod pour with PAC in water...this gives a 2,5V

please review what kind of chemical formula during equilibrium and during recharge? why voltage is droping or how to make this setup more better and stable as battery?

• What PAC stands for ? – Poutnik Dec 13 '20 at 8:46
• It's no use trying with aluminum. As soon as a piece of aluminum is in contact with air, its surface gets oxidized and covered by a thin and continuous layer of aluminum oxide, which is insulating and stops all electrochemical reaction. If you prevent this formation for example by amalgamation, the metal reacts quickly with air and with water, according to : $\ce{2 Al + 6 H2O -> 2Al(OH)3 + 3 H2}$. So it is destroyed and cannot be reduced to Al metal later on. The only way for Al to generate electrons in a battery is to use a non-aqueous solvant like toluene in contact with Al and AlCl3. – Maurice Dec 13 '20 at 9:59
• Aluminum works in a strongly alkaline cell, where the alkali can erode through the surface oxide film. Such a cell can provide temporary service, but the aluminum quickly reacts with the alkali and water, forming an aluminate. – DrMoishe Pippik Dec 14 '20 at 2:52
• PAC is poly alumunium Chloride – Hertog Dec 15 '20 at 9:02
• Poly Aluminium Chloride (PAC), is a water-soluble inorganic polymer between AlCI3 and Al(OH)3, its general formula is [Al2(OH)nCl6-nLm]. I already tried submerge alumunium foil in PAC solutuon and its not corroding...what is your comment on this? and the voltage is at least 1V wirh 1,80 mA of current on load 5k ohmi – Hertog Dec 15 '20 at 9:15