updated 10:20 am EDT, Thu July 17, 2014
Consistent with recent rumor
A photo obtained by French website NWE depicts what's claimed to be a 1,810mAh battery for the iPhone 6. The part is consistent with a recent rumor, and represents roughly a 16 percent improvement over the iPhone 5s. If it's authentic though, any gains will probably be offset by the extra power demands of the 6's 4.7-inch display, and possibly its A8 processor.
Apple is typically able to make efficient use out of batteries through software and hardware optimization, but a 1,810mAh battery could be disappointing to people who were hoping Apple would make the phone more competitive with Android rivals. Some high-end Android devices are able to last a full day or more on a single charge, whereas an iPhone 5s can typically only last several hours.