"I celebrate myself."
"Song of Myself" is the best-known and most influential poem of the American author Walt Whitman, first appearing in the 1855 edition of Leaves of Grass. The question asks about the binary of life and death in this poem, but I would argue that Whitman rejected binaries in his work. Whitman is the great poet of acceptance and embrace. He sees everything in life, both good and bad, and takes it into himself. Everything he becomes is part of him and his song, which then becomes the song of all mankind. While he had firsthand experience with death from his hospital work in the Civil War, I don't think he fears death or sees it in a traditional way. He goes so far as to say "The smallest sprout shows there is really no death" (line 116).
So while death is present in the poem, it is not treated in a negative way. Indeed, the poem is bursting with life. All of life, for Whitman, is good. Whitman says yes to the world. This way of thinking marks an important break in the American tradition, which was heavily influenced by Puritans. The religious group was nothing if not dualistic in their thinking and exclusionary in their practice. It may be worth looking at Whitman's contemporaries, the transcendentalists Emerson and Thoreau. Their more naturalistic thought similarly rejected orthodox ways of looking at the world and at the self. So, while the poem does engage with both life and death, it doesn't really view them in a binary manner. And if there are any examples of binary thinking, life always wins in Whitman's world.