"To" is a preposition here and should be followed by a noun phrase or gerund phrase. "Benefit of" usually shows the cause of the benefit. "Benefit to" usually shows the receiver of the benefit. An example is "The benefit to the environment of recycling is generally understood." The following Google n-gram shows the relative frequency of "benefits of recycling," "benefits from recycling," and "benefits to recycling." https://books.google.com/ngrams/graph?content=benefits+of+recycling%2C+benefits+from+recycling%2C+benefits+to+recycling&year_start=1800&year_end=2019&corpus=en-2019&smoothing=3

"Benefits to ..." is poor English. "Benefits of recycling ..." is good English.

The sentence is not grammatical. There are many ways to say what you want to say without using "to" (as others have mentioned.). However, if you do want to use "to", you must decide what purpose it serves. There are two choices: (1) It can be an ordinary preposition. In this case it needs a noun as an object as Chris described. This noun (or noun phrase) can be provided in many ways: "There are benefits to the recycling of cell phones" "There are benefits to the practice of recycling cell phones" (2) "To" can be part of an infinitive ("to recycle"). If you decide to take this route, you must decide what grammatical purpose the infinitive will serve. Infinitives can be nouns, adjectives, or adverbs. Here's a noun example: "To recycle cell phones yields many benefits." Here's an adjective example: "Programs to recycle cell phones are beneficial." Here's an adverb example: "When we collect old cell phones to recycle them we create many benefits."

“There are a lot of benefits to recycle the cell phones although they are no longer of use as phones” or “There are a lot of benefits of recycling the cell phones, although they are no longer of use as phones” -No difference-

Simple answer: yes, this sentence shows connection between benefits and recycling cell phones. Another way to say this sentence: Recycling cell phones has lots of benefits.