Lithium hydroxide (LiOH, commonly used in its monohydrate form, LiOH·H2O) is a premium, highly reactive lithium precursor. It is the dominant choice for synthesizing ultra-high-nickel layered oxide cathodes (Ni≥80%, such as NMC811 and NCA) and is widely used in fabricating oxide-based solid-state electrolytes (SSEs) like Garnet-type Li7La3Zr2O12 (LLZO) via low-temperature or liquid-phase pathways. Compared to lithium carbonate (Li2CO3), LiOH features a significantly lower melting point and a lower thermal activation barrier, allowing solid-state reactions to proceed rapidly at temperatures where the target crystal lattice is thermodynamically optimized.

For state-of-the-art high-nickel cathodes, LiOH is mandatory, and Li2CO3 cannot be substituted. High-nickel layered oxides (LiNi0.8Mn0.1Co0.1O2) are structurally unstable at temperatures exceeding 750°C to 800°C, where Ni^{2+} ions spontaneously migrate into the Li+ structural sites (a degradation mechanism known as cation mixing). Because Li2CO3 requires temperatures >800°C to fully decompose, utilizing it results in an incomplete reaction with high structural disorder.

(1) Pure Oxygen Atmosphere: The calcination must be carried out under a flowing, pure oxygen (O2) atmosphere rather than ambient air. This forces the oxidation of Ni^{2+} to the desired Ni^{3+} state, which is essential for maximizing specific capacity. (2) The Carbon Dioxide Threat: High-nickel precursors will aggressively absorb trace atmospheric CO2 during handling, turning back into surface Li2CO3. This creates an insulating layer that triggers slurry gelation during battery manufacturing and gas evolution (CO2 outgassing) during high-voltage cycling. Therefore, high-nickel materials are blended and transferred under strict climate-controlled environments with dry, CO2-free air.

While Li2CO3 is favored for standard high-temperature solid-state LLZO sintering (>1100°C), LiOH is the preferred precursor for modern low-temperature sintering, sol-gel, and hydro-chemical synthesis routes designed to prevent excessive lithium volatilization. (1) Mechanism: By using LiOH combined with acetate or nitrate co-precursors in a liquid solution, a highly homogeneous molecular gel is formed. Upon drying and calcining, the low melting point of LiOH drives the nucleation of the cubic garnet LLZO phase at temperatures as low as 700°C to 850°C. (2) Lithium Compensation: Even though the lower processing temperatures enabled by LiOH reduce overall lithium loss, a 5 to 10 wt% lithium excess is still typically integrated into the precursor batch to offset any high-temperature volatilization during final ceramic densification.

Notes: Please store the LiOH*H2O powder in a dry place (glovebox is preferred).

References: 

1. Y. Zhang, et al. Self-Stabilized LiNi0.8Mn0.1Co0.1O2 in thiophosphate-based all-solid-state batteries through extra LiOH, Energy Storage Materials, 2021, 41, 505-514
2. M. Y. Song, et al. Electrochemical properties of LiNi1−yCoyO2 cathode materials synthesized from different starting materials by the solid-state reaction method, Adv. Mater., 2009, 1625-1631