Welcome Kris, I don't have studies ready to cite, but do believe that like other battery types, our lithiums will gradually improve with use after a long dormancy.
Your driving skills certainly will. I've considered myself a hypermiler for years, but only hypermiled when I wanted to. (Yeah yeah, I may be a speed demon, but I can stop driving like a jackrabbit any time I want to...).
The i has a way of curing this when you realize that by avoiding a single charging stop on any significant trip, you save more time by driving slower. I do a 55 mile/89 km round trip on most Saturdays that can't be accomplished aggressively without a charging stop, but is easily done with 2-3 bars remaining if one navigates sedately. (Disclaimer- on the West Coast I-5 Electric Highway from Tacoma-Portland, the DCFC spacing of 21-36 miles means that an i-MiEV can't skip a station with 80% SOC, but you can go fast between 'em!) Watching CanION a few times makes you a better driver for any vehicle even after the display goes dark. As proof, this past weekend on a 360 mile round trip to Grandma's in our 14 year-old, 175 kilomile minivan, I got over 24 mpg on a journey that for years has averaged 21-22 mpg. Simply staying out of the 'wolf packs' of aggressive drivers and getting off the gas as soon as one sees brake lights far ahead makes for a smoother drive and didn't cost any noticeable time. Timing the traffic lights and making strategic highway lane changes rather than reflexively jumping into every opening that appears let this tortoise beat several impatient hares down the road.
I still don't have the patience to stay behind a professional truck or bus driver for as long as I could, preferring to have a change of view. I'm not advocating danger-close drafting, but CanION helps one to measure the benefits of drafting even at reasonable following distances..
2012 i-SE "MR BEAN" 110,300 miles
2016 KIA SOUL EV, 90 kW, 27 kWh, 34k miles
2000 Mazda Miata EV, 78 kW, 17 kWh
1983 Grumman Kurbwatt EV,170 kW, 32 kWh
1983 Mazda RX-7 EV 43 kW 10 kWh
1971 "Karmann Eclectric" EV 240 kW 19 kWh