Yes, you can put Banana peels in compost. Banana peels are a good source of Potassium, which is also beneficial for the growth of the plant. These peels also contain other nutrients such as Phosphorus and Calcium. These two elements are also as beneficial as Potassium. The other benefit of using Banana peels is they decompose faster than most fruit peels. It means you can also use these peels in your vermicompost production process. The earthworms will surely feast on them.  Note: Don't forget to chop the peels into small pieces before adding them to your compost pile.