Regulating Lithium Plating Behavior in Lithium‐Metal Batteries via Molten‐Lithium Processing With Inorganic Additives

Why It Matters

The SGI directly addresses dendrite growth and low Coulombic efficiency, the chief obstacles to commercial lithium‑metal batteries. Its simple in‑situ formation could speed deployment of high‑energy cells for EVs and grid storage.

Key Takeaways

• Molten lithium + ZnF2 creates LiZn alloy and LiF gradient interphase
• LiZn layer lowers nucleation overpotential, speeds Li+ transport
• LiF top layer forms stable inorganic SEI, blocks dendrite growth
• Symmetric cells cycled 3000 h at 4 mA cm⁻², 16 mAh cm⁻²

Pulse Analysis

Lithium‑metal batteries promise energy densities exceeding 400 Wh kg⁻¹, yet uncontrolled dendrite growth and unstable solid‑electrolyte interphases have stalled their market entry. Traditional coating strategies rely on single‑layer films that cannot simultaneously address ion transport, mechanical robustness, and air stability. Recent research therefore focuses on engineered interphases that can dynamically manage lithium plating while resisting degradation under practical current densities.

The newly reported self‑assembled gradient interphase (SGI) leverages a straightforward molten‑lithium reaction with ZnF₂ to form a vertically graded architecture. The lower LiZn alloy sublayer offers strong lithiophilicity, reducing nucleation overpotential and facilitating rapid Li⁺ diffusion. Above it, a LiF‑rich layer provides high ionic conductivity and exceptional resistance to moisture, acting as an inorganic solid‑electrolyte interphase that curtails dendrite protrusion. In symmetric cell tests, this dual‑layer configuration sustained 3,000 hours of cycling at 4 mA cm⁻² with a capacity loading of 16 mAh cm⁻², outperforming most single‑coating benchmarks.

From a commercial perspective, the SGI’s in‑situ formation eliminates the need for complex deposition equipment, making it compatible with existing lithium‑metal manufacturing lines. By delivering both safety and performance gains, the technology could unlock higher‑energy packs for electric vehicles, extending range without sacrificing cycle life. Moreover, the approach is adaptable to other inorganic additives, opening avenues for further optimization of interfacial chemistry. As the industry seeks scalable solutions to bridge the gap between laboratory breakthroughs and mass‑market products, gradient interphases like SGI are poised to become a cornerstone of next‑generation battery design.