The current homemade cell is easily constructed in a mason jar. It produces 1.2 volts and up to about 1Ah.
The following "white papers" give the straight facts
on cell construction, distilled down from the many sources here,
and including actual construction of simple cells.
I think that these papers can save you many many hours of research, and separate "fact from fantasy."
If you find them (and this site) useful, and want to donate a few dollars toward the sizing up project, I've added donation link below.
There is NO OBLIGATION WHATSOEVER to donate to the project, but I thank you if you do!