You're right but drawing the wrong conclusion. The heat that's produced as the battery charges is a byproduct of the resistance of the chemistry. So when you

You're right but drawing the wrong conclusion. The heat that's produced as the battery charges is a byproduct of the resistance of the chemistry. So when you get a more efficient chemistry it increases both cycle life and charge rate, they're two symptoms of the same property. Its a win/win not a tradeoff (although you can still chose to tradeoff one for the other in your product design).