Welcome, S_Ch_S!
You want metallic aluminium, is that it ?
Electrolysis of aluminium is difficult with limited means. It's not done in aqueous solutions, because the redox potential lets produce hydrogen instead of metallic aluminium - and aluminium makes additional reactions. You could check and meditate that list
https://en.wikipedia.org/wiki/Standard_electrode_potential_(data_page)
Metallic aluminium is obtained industrially by electrolysis of a molten salt, without water not solvent.
To grow crystals, it's easier to melt and solidify some aluminium alloy. For instance if you try to weld an Al-Cu4-MgZn alloy with TIG equipment, you obtain crystals about 2mm big, that are highly unwanted as they make a brittle weld seam. Slower solidification, if possible oriented, would grow bigger crystals.