There is a chart here: https://www.researchgate.net/figure/Advances-in-energy-density-of-selected-battery-types-by-year_fig2_294580055 https://www.researchgate.

There is a chart here: https://www.researchgate.net/figure/Advances-in-energy-density-of-selected-battery-types-by-year_fig2_294580055 https://www.researchgate.net/figure/Advances-in-energy-densi... I am a bit confused by the units but it seems to be growing, tho the data cuts off at 2005. Another chart is here: https://physicsworld.com/a/lithium-ion-batteries-break-energy-density-record/ https://physicsworld.com/a/lithium-ion-batteries-break-energ..., still does not seem exponential, looks kind of of linear to me.