At last some worthwhile submarine news.
Italy is buying and will probably do the building of what I think are the world's first 4 submarines that combine AIP and Lithium-ion Batteries.
These will be Type U212 NFS (for Near Future Submarine) Todaro Class Batch-III submarines.
AIP and Lithium Batteries will probably allow them to fully submerge longer than any other "conventional" (diesel-electric) submarines.
See a good description with a cutaway diagram at https://www.navalnews.com/naval-news/2020/12/italys-new-type-u212-nfs-submarine-program-moving-forward-with-occar/