A photo of your arrangment would be helpfull. On reading the description, adequate surface area exposed to a sufficient quantity of electrolyte could be an issue. That would be basic operation of a chemical battery though, so i am at a loss.
I have a copy of the rebuild manual for the old edison batteries made of plated plates and
wood seperators. Its been a while, but it covers the conditions that hinder operation and the fashioning of replacement parts.
This is an area where many of us
should study. We built simple saltwater batteries from paper towel, dis-similar metal washers and saltwater in electronics at technical school, but power and storage was only
enough to demonstrate the principle.
As simple as they are, rechargable elecro-chemical storage batteries are an applied science.
Love to see some details and information compiled here by educated folk on the subject and some projects.