Voltaic is electric. You're familiar with electricity from living here, yes? A sufficient dose of it applied to a human being will stun them - enough electricity could actually kill a person, but that's not what the voltaic bombs were designed to do. When thrown, they release a charge that will stun anyone within range who doesn't have a grounding rod in their boot - not kill them, just give them a shock long enough that a person who's less suited to fighting than to running and hiding can run and hide.