https://techcrunch.com/2017/09/13/apples-new-iphone-8-and-iphone-x-support-fast-charging/

Want to get 50 percent of your battery life back with just 30 minutes of charging? You can do that with the iPhone 8 (and 8 Plus) and iPhone X (via Engadget). These are the first phones put out by Apple that will support a quicker charge rate if you have a higher capacity charger – though you’ll have to pick one of those up separately to take advantage.

Like the iPad Pro before it, the new iPhones actually support faster charging rates than their provided charging dongles can provide; using Apple’s 29-watt USB-C charger (the one which ships with the MacBook) and a USB-C to Lighting cable will help you top up your device much faster. You can also use a 61 or 87-watt charger, if you happen to have one of those from the purchase of a new 13 or 15-inch MacBook Pro.