Lithium is element number 3, a metal with the symbol Li. Its atomic weight, 6.94, is the smallest of any metal element. It is the “lithium” in lithium-ion batteries.
Atomic number 36.94
LiLithiumリチウム (richiumu)
Symbol
Li
Atomic weight
6.94
Place in the table
Period 2 · Group 1
Atomic weight from the Chemical Society of Japan, “Table of Standard Atomic Weights with Four Significant Figures (2026)”.
Named for “stone”
The symbol Li comes from the Latin lithium, from lithos, Greek for stone. Lithium was discovered in 1817.
On the periodic table it sits directly below hydrogen, in the second row of Group 1, the same column as sodium and potassium.
The lithium-ion battery
The 2019 Nobel Prize in Chemistry was awarded for the development of the lithium-ion battery. One of the three winners was Akira Yoshino of Japan.
In the patent that Yoshino and his colleagues filed in 1985, the positive side used a compound of lithium and cobalt, and the negative side used a carbon material.
Think about it
Q1Look for things around you that have a rechargeable battery inside.
Q2An element named for “stone” became the star of batteries. Isn’t that interesting?
Q3Why do you think a battery uses different materials on its positive and negative sides?
There is no single right answer. Talking it over with someone at home is a good way to learn.
Did you know? — The negative side of Yoshino’s battery used a carbon material. In the Room of the Elements you can also read the pages on carbon (C) and cobalt (Co).