Remember that fuel-cell-powered iPhone we talked about a couple weeks ago? Seems like Apple was already on the fuel cell game before that. The Cupertino company has filed for a patent on fuel cell technology for powering "portable electronic devices for days or even weeks without refueling." The patent application was filed back on March 19 and published a few days ago.
At first glance, it would seem that the patent refers to MacBooks, given its discussion of a MagSafe connector and a PWM fan for the fuel cell. However, that's only one of several possibilities, as the patent specifically states the interface "is not limited to a MagSafe connector, and in general can include any type of connector that provides power and bi-directional communication." The exact composition of the fuel itself is also up in the air, since the patent lists enough chemicals to make Walter White's eyes gleam.
As with any big tech company, Apple's patents don't always bear fruit in the form of actual products. However, it's safe to say the prospect of having a phone, tablet, or laptop powered for days or weeks on end has undeniable appeal.