Generally you need a USB cable to recharge your power bank. If you need a more convenient way, the following BOLT portable backup battery with wall charger may be more suitable for you.
The BOLT is a practical portable power bank that measures 2.75 x 1.33 x 1.10 inches. As we can see from the images, the backup battery features simple and portable design along with multiple optional bright colors, and comes with a built-in wall charger in order that you can easily recharge it via wall outlet even if you forget to carry a USB charging cable. Moreover, the power bank also features a built-in 3000mAh backup battery, no doubt you can use it to extend the battery life of your smartphone or charge other mobile devices, while integrated LED indicator shows the status of the backup battery.
At present the inventor of the Bolt is raising fund at Kickstarter. Pledging $40 will let you own the backup battery with wall charger. If you’re interested, jump to Kickstarter official site for more details.