5. Changes in performance and applications

5.1 Performance changes

The main performance criterion of Li-ion batteries is energy density by mass and/or volume . In 1992, the energy density stored in a cylindrical cell 18650 is 80 Wh · kg ^-1 and 200 Wh · L ^-1 . The progress achieved continuously thereafter resulted in a more than tripling of these values (280 Wh · kg ^-1 and more than 700 Wh · L ^-1 in 2018) (figure