A Weibo report has surfaced that indicates the iPhone 7 may have a slightly larger battery than the current generation iPhone 6s and iPhone 6s Plus. According to the poster, the iPhone 7 will include a battery with a 1735 mAH capacity and iPhone 7 Plus will feature a 2810 mAH battery. On both models, this is (slightly) more than the current-generation iPhones. The iPhone 6s and iPhone 6s Plus have batteries with 1715 mAH and 2750 mAH respectively.
Battery capacity and battery life are different things of course. Although additional capacity gives the device more power budget to play with, the efficiency of the components will influence the final battery life ratings. The iPhone 6s and iPhone 6s Plus represented a significant downgrade in capacity but battery life remained constant, for example.
Even if the Weibo rumor comes true for iPhone 7, the iPhone 6 and iPhone 6 Plus will still have had the best battery capacity of any iPhone, with 1810 mAH and 2910 mAH batteries. Apple has generally stuck to the same battery life across iPhones for the last few years, ignoring the juncture when Apple made the devices substantially larger with 4.7 inch and 5.5 inch screens.
Apple has typically used increases in battery capacity to improve performance and used component efficiency improvements to make products thinner. The company sells an official battery case (released last year) for those longing for additional hours of use on the 4.7-inch iPhone.
Although the rumored numbers for iPhone 7 are higher, the delta is not significant enough to suggest Apple is making better battery life a priority for its upcoming iPhone (perhaps the A10 is slightly less power efficient than the A9?). Battery life is likely to be comparable to the 6s, if this rumor is accurate.
As always, uncredited reports on Chinese social networking sites should be interpreted with some skepticism. That being said, such leaks turn out to be correct frequently enough to warrant coverage.