'Juice' offers disposable chargers that were designed to be used and thrown away when they are no longer needed.
The chargers come in packs of two or four and come in two different kinds -- one that is able to plug into Android phones and another that can be used for iPhones. The device charges phones when they are dead and can take them up to 40%. Although they may be somewhat wasteful and are not suited for every day use, smartphone owners could find use for these charging devices for days in which they are on the go, for when they are spending time outdoors, or when they are dealing with power outages.
These disposable chargers are certainly not for daily use but would make for excellent items in the case of an emergency.