Strategy for Lowering Li Source Dosage While Keeping High Reactivity in Solvothermal Synthesis of LiMnO2 Nanocrystals

The lithium resource is becoming increasingly scarce due to the increasing use of lithium ion secondary batteries. To obtain LiMnO2, however, using a hydrothermal method, a high concentration of LiOH is required, namely, Li/Mn molar ratios in raw materials that are usually larger than 13. In this letter, we present a new strategy for drastically lowering the Li dosage based on the fact that the LiOH solubility is high in water but sparingly soluble in ethanol. Well-crystallized LiMnO2 nanocrystals can be produced in miscible solvents with a Li/Mn molar ratio as low as 1.05. The results strongly suggest that a high Li+ concentration in the water phase would be beneficial for manganese oxides to form a layered structure, while the reactivity of Li+ accelerates its reaction with Mn2O3.