From The Economist. Besides finding it interesting I was reminded of the kWh discussion a few days ago 
https://finanz.dk/the-tortoise-and-the-hare-how-to-hybridise-batteries-and-supercapacitors-science-technology/
A different, somewhat more conventional, incremental tack.
The next incremental step, solid state still lithium based batteries. From Financial Times.
https://finanz.dk/quantumscape-can-battery-pioneer-live-up-to-the-hype/