Yes, between typically functions as a preposition (e.g., “There were short breaks between the lectures”).
However, it is classified as an adverb when placed at the end of a phrase like this: “There were three lectures with some short breaks between.”
“Between” is often interchangeable with “in between,” but note that you can’t spell “in between” as either inbetween or in between—it’s always spelled as two words.
A QuillBot Grammar Check can help ensure you’re using words like “between” correctly.