Batteries should not burst into flames.

Anatomy of a lithium-ion battery PHOTO (COLOR): Watch how lithium ions and electrons move when a battery is discharging and charging. The lithium ions move within the battery to the cathode through an electrolyte. K. N. Wood et al/ACS Central Science 2016 With a lithium-metal anode, the battery would be doing the thing avoided in normal lithium-ion batteries: making metallic lithium during its recharge. [Extracted from the article]