• Short version: yes.

    Long version: No lithium, no cobalt, usually no nickel, usually no manganese, and no graphite. I’m not sure what electrolytes will prove best, but multiple metal-oxide cathodes are viable (in addition to prussian-blue analogues), and the anode is just hard carbon (basically charcoal). The raw components are plentiful on every continent. Depending on chemistry, some of the steps are potentially toxic if mishandled (chromium oxide), but no one to my knowledge has raised any major red flags.