A repetitive but generally reliable leaker has listed specifications for the forthcoming iPhone 18, and one significant update may be increased battery life.

Apple’s current iPhone 17.
Leaker Digital Chat Station has recently taken to reposting previous rumors as new, including ones about the iPhone 18e. Much of their latest report is, again, a repeat, but it does add that the battery life will be extended.
The post is written on the Chinese social media site Weibo and this detail about the battery comes at the end of a short list of iPhone 18 specifications:
Rumor Score: 🤔 Possible