Yes, but the way in which they have solved this is partially the reason why many sans-serif fonts suck from this point of view.
Serifs have appeared as a feature of the Latin letters of the inscriptions in stone of the Roman Empire, which are the model for the present capital letters.
On the other hand, the model for the present small letters are the letters of the manuscripts of the Carolingian Empire, written with pen (i.e. goose feather) on parchment.
The small letters originally did not have serifs. The small "l" letter had a right hook at its lower end, which distinguished it easily from an "I".
Serifs were added to the small letters, in imitation of the capital letters, only in the first books that were printed with "Antiqua" letters, in Italy, after the invention of printing.
The addition of a serif at the low end of "l" has lead to the removal of the right hook that it had previously. When sans-serif fonts were created in the 19th century, they have removed the serifs from the letters, so by removing the differently-shaped serifs from "I" and "l" they have become hard or impossible to distinguish.
The wiser typeface designers have realized that this is wrong and they have restored to small "l" the low right hook that it had at its origin in the Caroline script, distinguishing it from capital "I" even in a sans-serif font.
Unfortunately, too many sans-serif fonts have continued to perpetuate the mistake of removing the serifs from small "l" without restoring its original low right hook.