Burning wood has a energy density of roughly 10 MJ/kg. Lithium batteries have about 0.875 MJ/kg of electric energy. Lithium metal burns at about 43.1 MJ/kg. So

Burning wood has a energy density of roughly 10 MJ/kg. Lithium batteries have about 0.875 MJ/kg of electric energy. Lithium metal burns at about 43.1 MJ/kg. So yeah. By a factor of 4 at least.