Re: Why is there no current with an open circuit?

There is current in a galvanic cell, even when not part of a circuit.  This leakage current exists in any battery and will eventually cause an unused battery to go dead.  This is one of the reasons battery manufacturers now commonly put a “use by” date on packaging.

Leakage current can be minimized, but never completely eliminated. The manufacturer accomplishes this through the battery design. The user can also affect this through storage; storing a battery in a cool place slows the chemical reaction.