Is there any difference between sentences 'I am home' and 'I am at home'?
If there is no difference, which one is perfect to use?
Yes, there is marginal difference. The preposition ‘at’ indicates that the noun ‘home’ that follows it, establishes a point in relation to which another object ‘I’ is positioned.
So: “I am at home” always means that I am positioned or staying at home, and this is normally used.
Where as the term “I am home” can be used to mean; I am safe after some incident. Look at the following sentences:
My friend had a surgery for removal of a tumor. I am happy to hear that he is home and doing well.