The Core Role of Battery Grade Nano Lanthanum Oxide

Battery-grade nano-lanthanum oxide is not merely a raw material additive, but a meticulously engineered functional material. Its core function leverages the unique chemical properties of lanthanum and the surface effects of nanoscale dimensions to provide critical stabilization, reinforcement, and catalytic effects within electrode materials and interfaces. The specific mechanisms are as follows: 

1. Structural Stabilizer: In solid-state batteries, La exists as LaO₈ dodecahedrons, forming the primary framework of LLZO crystals. The La³⁺ ion (approximately 1.06 Å) has a larger radius than common Ni²⁺/Ni³⁺, Co³⁺, or Mn³⁺/Mn⁴⁺ ions. When La³⁺ enters the lattice, its large radius and high charge create strong La-O bonds with surrounding oxygen ions—akin to reinforcing structural load-bearing columns in building frameworks, significantly enhancing crystal stability. During deep charging/discharging (especially at high voltages), transition metal ions (e.g., Ni²⁺, with Li⁺-like radius) in lithium layers tend to migrate to lithium sites (cation mixing), triggering irreversible phase transitions from layered structures to amorphous spinel or rock salt phases, leading to capacity fade. The "pinning" effect of La³⁺ effectively anchors the lattice, suppressing metal ion migration and dramatically slowing phase transition processes. At high voltages, unstable lattice structures may release oxygen, posing safety risks. Stable La-O bonds increase the energy barrier for oxygen evolution, inhibiting oxygen release and thereby improving thermal stability and safety.

2. Ion Conduction Accelerator: Based on the charge balance principle, introducing high-valence La³⁺ ions forces the lattice to generate lithium-ion vacancies (defects). These vacancies serve as essential pathways for lithium-ion transport. An increase in vacancy concentration directly expands the available migration paths and reduces migration barriers, thereby significantly enhancing ionic conductivity.

3. Interface Buffering Agent: Incorporating nano-lanthanum oxide (La2O3) into the cathode material surface enhances interfacial contact with the solid electrolyte and alleviates stress. During charge-discharge cycles, the cathode undergoes thermal expansion and contraction, creating mechanical stress between the flexible material and rigid electrolyte that may cause contact failure or even cracking. The nano-La2O3 layer acts as a functional buffer, effectively distributing stress and maintaining physical contact. Additionally, by promoting uniform lithium-ion migration, this modified layer facilitates even lithium deposition on the anode side, thereby suppressing lithium dendrite growth and improving safety.