There are already plenty of decent power banks that can charge your smartphone on-the-go. The NEBO PaL+ Multitool does that and more. It is a 3-in-1 power bank, flashlight, and folding knife. The flashlight has 400 lumen output. The PaL+ has a 3-inch folding blade that can be removed for travel.
The NEBO PaL+ has a 2200mAh rechargeable battery. It has an anodized aluminum construction. It is water & impact resistant. It weighs only 0.44lbs, so you can easily carry it around.[Official Site]