https://www.techradar.com/news/ankers-new-power-banks-are-specifically-made-to-charge-your-nintendo-switch

The portability of the Nintendo Switch is its unique selling point, but you may sometimes be gutted to find it run out of charge so Anker has partnered with the company to make officially licensed power banks.

Two new portable chargers from Anker are designed specifically to charge up your Nintendo Switch, although they will also work to charge up your phone, tablet and other gadgets.