I disagree with John. "Between" is the correct preposition. "In between" occurs usually because "in" is part of a phrasal verb e.g. "He cut in between the two cars" ("cut in" + "between") Or "in-between" can be an adjective e.g. "My son is at that in-between age, not a child anymore but not yet an adult."" However, in practice, I think many people use "in between" and "between" interchangeably today (especially when speaking). Apparently this is more common in the US (hence John's answer). I don't think many people would notice if you mixed up these words. He are some places you can read about this: https://www.dailywritingtips.com/between-vs-in-between/ https://www.grammarly.com/blog/in-between-or-inbetween/

There is no difference in any examples that I can think of.