Hmm... No.
It's a move similar to Memento, your Pokémon faints without fail when you use it. Even if you think about this thing as if it were in real life: An opposing Pokémon attacks... Your Pokémon has Focus Band... The Pokémon focuses... And survives the attack. However, when using Selfdestruct, Explosion, Memento and similar (if any more exist, I can't think of any right now), the Pokémon deliberately destroys itself. That's a kind of explanation as to why it doesn't work. The Pokémon faints intentionally to deal as much damage as possible, or, in Memento's case, to lower the opponent's stats as much as it can.