I have a question about a battery I made. It has an aluminum cathode and a graphite anode. electrolyte is saltwater. When I measure the potential it reads 0.73 volts. Then I temporarily connected a 3.7 volt battery to it, for <5 seconds. Now it reads 1.12 volts. If I remove the graphite and replace it with a fresh one the voltage reads 0.73 volts again. Putting the original graphite back in and it reads 1.12 volts again. Then I discharge it for awhile and the voltage drops, but when stopping the discharge it goes back to 1.12 volts again. My question is how was the graphite changed? I don't know who else to ask. Help me Obwan.