- Lithium hydroxide (LiOH) is an inorganic compound composed of lithium, oxygen, and hydrogen. It is a white, hygroscopic crystalline solid that is highly soluble in water and slightly soluble in ethanol. In aqueous solution, it dissociates completely into lithium ions (Li⁺) and hydroxide ions (OH⁻), making it a strong base.
- Lithium hydroxide exists in two forms: anhydrous and monohydrate (LiOH·H₂O). The anhydrous form is typically prepared by heating lithium carbonate (Li₂CO₃) with calcium hydroxide in a metathesis reaction, whereas the monohydrate is more commonly encountered due to its tendency to absorb moisture from the air.
- Chemically, lithium hydroxide exhibits strong basicity and reactivity typical of alkali metal hydroxides. It reacts vigorously with acids to form lithium salts and water, and with carbon dioxide in the air to form lithium carbonate (Li₂CO₃). Upon heating, especially in its monohydrate form, it can lose water and revert to the anhydrous state. It is also stable under normal conditions but should be stored in tightly sealed containers to prevent atmospheric CO₂ absorption, which can compromise its purity.
- Lithium hydroxide has several critical industrial applications. One of its most significant uses is in the manufacture of lithium-ion batteries, particularly in the production of cathode materials such as lithium cobalt oxide (LiCoO₂), lithium nickel cobalt manganese oxide (NCM), and lithium iron phosphate (LiFePO₄). Its high purity is crucial for ensuring the performance and lifespan of battery cells. It is also used in the lubricants industry to produce lithium-based greases, which have excellent thermal stability and are widely used in automotive and industrial machinery. In the ceramics and glass industries, lithium hydroxide acts as a flux to improve product characteristics like thermal shock resistance.
- In the space and submarine industries, lithium hydroxide serves a critical life-support function by scrubbing carbon dioxide from the air. It reacts with CO₂ to form lithium carbonate, thereby helping to maintain breathable air in enclosed environments. This application highlights the compound’s utility beyond traditional manufacturing roles, demonstrating its importance in specialized fields requiring reliable gas control.
- From a safety perspective, lithium hydroxide is corrosive and can cause severe irritation or burns upon contact with skin, eyes, or mucous membranes. Inhalation of dust or mist can irritate the respiratory tract. Therefore, it must be handled with appropriate personal protective equipment and stored away from moisture and acids. Environmental exposure should be minimized, as lithium compounds can be toxic to aquatic life at high concentrations.
- In the realm of research, lithium hydroxide continues to be of interest due to its role in emerging energy storage technologies and its interactions in electrochemical systems. Advances in battery design, especially solid-state batteries, often require ultra-pure lithium hydroxide as a precursor. As global demand for electric vehicles and renewable energy storage grows, lithium hydroxide remains a pivotal material in the transition to cleaner energy systems.
