I think there are quite a lot of things in that sentence that might not be as obvious as they first appear. What do you mean by 'alive'? What do you mean by 'sentient'? Why would 'alive' be definitionally required by 'sentient'?

Sentience seems to be the ability to experience, for there to be 'something that it is like' to be you. Life is pretty difficult to define, but generally has a lot more baggage than would be expected of something that could be a minimum requirement for the ability to experience.