yes it is certainly doable especially if you have a source of metal matching the anode/cathodes, so you dope them accordingly. Only issue is providing enough energy for this process to occur. If you mean actually using a pool as a big battery... yes that is also doable and many cheap metal fabs use pools for that purpose. It's also extremely dangerous, because you will need suitably large size pieces of metal and enough acid to make the water reactive enough. Cheap fabricators will string salvaged battery plates together and use the vat as a general dump for all battery acid. This is usually illegal.
warning: sometimes you might introduce too much energy into the equation and it might combust into a battery fire. Other times it will offgas and create a chemical emergency. Any leaks turns the ground around it into a superfund project. oh well
