This Battery Block for Xbox One from Nyko includes a charger, a 1200mAh rechargeable battery, and a replacement cover for the Xbox One wireless controller. The charger is compatible with any wall outlet or USB port, and can charge up to two batteries at the same time. A built-in LED indicator will inform you of when the batteries are ready, and these chargers can be linked together for a custom charging solution.
Please note that connecting more than two Charge Blocks requires a USB 3.0 connection.