LI is the elemental symbol of metallic lithium in chemistry; Lithium metal was first discovered in a rare rock by Swedish chemist A Alfvitsang in 18 17. According to the original Greek meaning, lithium is "rock". Lithium is a silvery white metal, which is very light and the lightest of all metals. Lithium is used in metallurgical industry. Adding a small amount of lithium (5/100,000) to copper can greatly improve the performance of copper. This is because lithium has active chemical properties and can react with harmful impurities such as oxygen, nitrogen and sulfur in copper to play the role of getter. Adding a small amount of lithium to metals such as aluminum and magnesium can improve their firmness, acid resistance and alkali resistance.