Protecting reactive alkali metals like lithium from atmospheric exposure is a well-established concept in chemistry achieved through coatings, inert environments, or chemical passivation, making citation unnecessary.
The claim that elemental lithium can be protected from reacting with the atmosphere is a matter of basic chemical knowledge and well-established scientific observation (e.g., storage under mineral oil or inert gas, passivation layers). None of the provided papers directly target this specific textbook fact as a novel research question, though several discuss battery anodes and surface protection. Per instructions, trivial/common knowledge claims should be designated as COMMON_KNOWLEDGE without requiring paper citations.