what metrics could you use for "progress"? Maybe a crowd-sourced thing where users can update the highest achieved density for each? Still there's other measure

what metrics could you use for "progress"? Maybe a crowd-sourced thing where users can update the highest achieved density for each? Still there's other measures that are probably even more important and harder to measure. Like adoption EDIT: actually I just realized I'm describing Wikipedia https://en.wikipedia.org/wiki/Sodium-ion_battery#Comparison https://en.wikipedia.org/wiki/Sodium-ion_battery#Comparison