A professional chemist recently sat down for a Reddit AMA about lithium ion battery technology. It didn't take long for someone to ask about battery life in phones. The Reddit user asked when they would be able to get 2-3 days of battery life. Dee Strand, the chemist, explained that we may never get there. As battery technology improves so does phone technology. So while batteries will continue to get better, our phones will require more battery life. It's a constant back and forth.