Will "iphone 6 battery replacement" the word I can optimize it?

I have a cell phone battery site, I would like to optimize the "iphone 6 battery replacement" the word, but not sure the word optimization is difficult? Is competition so intense? I am a novice, so I hope you help me look at the word is difficult to optimize it?
very thanks

who can help me ,thanks!

Here are the "on page" factor correlations for your search term:



Mobile first is a thing now:


An example of page weight hurting rankings:


How many sentences?


How many words do you need?


How well are TLDs other than com net and org doing?


Does the size of the site matter?




Degree of competitive keyword stuffing: