As I understand it, much of the "battery breakthroughs" are generally along the lines of attempting to create a balance between capacity, discharge-recharge rat

As I understand it, much of the "battery breakthroughs" are generally along the lines of attempting to create a balance between capacity, discharge-recharge rate, safety and cost. The conversion efficiency of most batters is pretty good, it's making a long lasting, high capacity, quickly discharging/recharging and safe battery that's also cheap that is difficult. While pretty much everything above is related to chemistry/conversion efficiency, I was just trying to define the efforts a bit more along the goals.