PowerSkin has announced its new battery case for the iPhone 5 — an accessory eponymously named PowerSkin ($80). A thin, one-piece silicone case, PowerSkin features a 1500 mAh battery, and claims to recharge the iPhone 5 up to 70 percent capacity. The case promises to deliver up to 6.5 hours of talk time, up to 8 hours of Wi-Fi, and up to 32 hours of audio playback. PowerSkin comes in black with an earphone extender for 3.5 mm headphones. It’s…