Comment by schiem

It depends on the AA battery, but you'd need 6 - 8 to get equivalent performance.

The Google Pixel 9 has a 4700 mAh battery at 3.9 volts. The total energy is around 18.3 watt hours.

A high capacity rechargeable AA battery is 2500 mAh at 1.2 volts, or around 3 watt hours. If you wired 3 AA batteries in series, and then 2 of those series in parallel (for a total of 6 batteries), that would give you 3.6v at 5000 mAh. 3.6 volts falls within a normal discharge curve for a lithium ion battery, so you probably wouldn't need a boost converter.