Nice for phones, but even better for cars
Currently cobalt is only used in Li-ion batteries for small stuff like phones because while it has the best energy density it's not seen as safe enough to use in larger items more subject to damage like power tools and cars. If this has the same/better energy density it could replace the cobalt in phone batteries and reduce the odd cell phone catching fire, along with shaving a few grams off the weight.
But it would really be a big win for electric cars, as they'd get a longer range due to the higher energy density over the non-cobalt Li batteries they currently use, in addition to its lower weight reducing power required (though it's mostly aerodynamic drag at highway speeds) This also addresses one of the it's-really-not-so-green objections to electric cars.