I don't believe Apple has released empirical data, but Apple has optimized phone charging built into recent versions of iOS (Settings > Battery > Battery Health and Charging). It will stop at 80% and then resume charging to 100% about an hour before you start using your phone every day. iOS tracks your daily habits to determine the start of your day.

In the most recent iOS versions, if it can determine when "clean energy" is available near your location, it will also try to charge only during those time periods. I don't think any 3rd party has determined if it is effective.