Admittedly I’m using figures found online, but…
I was thinking of the energy used in making a phone vs. the energy to charge it, regardless of any efficiency losses.
To make an iPhone takes 388 million joules.
To charge it from nil takes 7 watt hours, roughly 25 thousand joules. That’s about 9 million joules a year, assuming you do that every day (unlikely, but let’s be generous).
So to consume 388 million joules would take 42 years. That’s assuming 100% useful energy.
If the battery was at 80% efficiency and it consumed 8.75 watt hours per charge (6250 extra joules), it would take 62000 years of charging it every day for the waste to add up to a new phone.
I was using the embodied energy figures from here: http://www.wattzon.com/stuff/items/k9fmwte14tuxxadzktgj1baucj/kateul1aiv26yqzm9qifapx6t1