Lithiation

Lithiation is a chemical process in which lithium is introduced into a substrate, producing lithium-containing species. In organic synthesis, lithiation commonly refers to generating organolithium reagents by deprotonation or halogen–lithium exchange. In materials science and energy storage, lithiation denotes the intercalation or insertion of lithium ions into a host structure, such as graphite or layered oxides, during charge.

In organic synthesis, lithiation typically employs strong bases such as n-butyllithium or tert-butyllithium to remove a proton and form an organolithium compound, or to replace a halogen in an aryl or alkyl halide via halogen–lithium exchange, yielding reactive organolithium intermediates that can be quenched or used in electrophilic substitutions. Lithiation can be directed to specific positions by directing groups or directed lithiation strategies, often at low temperature in anhydrous ether solvents.

In energy storage, lithiation refers to insertion of Li+ into a host lattice, commonly graphite to form LiC6 during charging, or into silicon, metal oxides, or layered oxides. This process is typically reversible and underpins the operation of lithium-ion batteries; practical concerns include volume change, solid electrolyte interphase formation on anodes, and potential dendrite formation on lithium metal anodes.

Lithiation reagents are highly reactive and air- or moisture-sensitive; reactions are typically performed under inert atmosphere in dry solvents. Common solvents include tetrahydrofuran and diethyl ether, and reactions are often conducted at low to moderate temperatures to control reactivity and selectivity.