Additionally, a photograph of what is purportedly the battery that will power the iPhone 7, reveals that the cell has a capacity of 7.04 Whr. That is a 6.5% increase in capacity over the 6.61 Whr that the iPhone 6s battery contains. Without knowing the voltage, it would be impossible to get a capacity size for the cell in milliampere-hours (mAh). Comparing two batteries, the one with the larger Whr number will most likely offer longer battery life.
One reason why Apple has allegedly removed the 3.5mm earphone jack from the iPhone 7 and Apple iPhone 7 Plus was to allow a larger sized battery to fit inside the device. If this image is legit, it would appear that the iPhone 7 will come with a slightly improved battery life. It might not be enough to make the power users happy, but any increase in iPhone battery life will be well received.