Trimethyl citrate is a citrate ester that can act as a solvent for certain lithium salts. The solubility of lithium in trimethyl citrate largely depends on the specific lithium compound being used. Generally, lithium salts that are more ionic and have higher solubility in organic solvents tend to dissolve better.
Lithium salts, such as lithium acetate or lithium citrate, may be more soluble in trimethyl citrate than other, less soluble salts