Although Michael called it a 'battery', in truth, it was actually just a bomb that was a lot less volatile to explode.
Back when he was first experimenting with Unity, he found that if he created a small enough sample with all eight elements, it wouldn't just explode outright with the smallest of bumps. It could give a reliable source of limitless energy.
The only downside this had was the amount of power that could be produced, making it useless for things that needed lots of electricity like refrigerators, cars, etc.
It was only used as a battery for small trinkets like the Reborn watches and flashlights.
And it just so happened that it was perfect for a smartphone.
Michael raised his hand, motes of light gathering at his palms. All eight mana swirled in the air above before shooting down towards his hands, gathering into a small clump of prismatic light.
