Credit: Twitter/Realme GlobalRealme has revealed a concept phone with a 15,000mAh battery.The phone is less than 9mm thick and can last for up to five days.The device uses a battery with 100% silicon content, effectively ruling out mass production for now.The advent of silicon-carbon batteries has resulted in many smartphone brands offering bigger batteries than ever before. We’ve already seen HONOR and vivo launch phones with ~8,000mAh batteries in relatively slim designs. Now, realme has revealed a rather impressive concept phone.Realme has announced a concept phone with a 15,000mAh battery. We’ve seen rugged phones with larger batteries, but this typically comes with the side-effect of a thick, heavy design. However, realme manages to fit all this juice into a form factor that doesn’t look like a brick. In fact, the company claims the concept phone is only 8.89mm thick.