85% to 90% is nowhere near? Total nonsense.
When it comes to specific density the best NiMH is comparable to some of the lower density Li-ion cells but if you compare the best of what each can do its not close.
he big advantage with lithium is that it dosnt self discharge.. picking up devices with flat batteries and the only way you could guaranty they would function was charge them before use did my head in..
i go back to the ni-cad days and do know what the standard procedure used to be.. "charge overnight before use".. not quite the same as just picking up and using which is what lithium provides..
i have lithium batteries that have stood for several years you can still just pick them up and use them.. mostly they will still have a good charge in them..
That and internal resistance, and charge cycles are also aspects where Li-ion blow away NiMH. Not only do they hold more power (amp hours), you can access more of it (watts), you can put it back in faster, they hold their charge longer (self discharge), you can charge them more times (life cycle), and you don't have to specific about how you charge them (maintenance).
I remember using my grandpas pretty expensive Milwaukee NiMH tools as a kid and performance was not even close, and the tools weighed a ton compared to even mid range modern Ryobi or Ridged tools let alone a modern equivalent Milwaukee, Dewalt, Bosch or similar which perform essentially as good as a corded tool.