Engineering thin 3D Li-composite foil negative electrodes with high mechanical toughness.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Three-dimensional lithium metal anodes face challenges balancing mechanical strength, thinness, and electrochemical performance.
• Existing lithium metal electrodes often suffer from poor durability and limited cycle life due to dendrite formation and mechanical degradation.

Purpose of the Study:

• To engineer a novel free-standing lithium-composite foil negative electrode for high-energy lithium metal batteries.
• To overcome the trade-offs between mechanical robustness, thin processability, and electrochemical performance in lithium metal anodes.

Main Methods:

• Integration of a lithiophilic lithium-zinc (Li-Zn) alloy with a lithium nitride (Li3N)-enriched carbon nanotube (CNT) network.
• Fabrication of a composite foil electrode with enhanced mechanical properties and controlled lithium deposition.
• Electrochemical testing of the composite electrode in coin and pouch cells with a high-nickel cathode (LiNi0.8Co0.1Mn0.1O2).

Main Results:

• Achieved a 12-fold enhancement in rupture toughness (1.3 × 10⁶ J/m³) compared to bare lithium.
• Enabled fabrication of thin (<10 μm) electrodes resistant to pulverization during deep lithium plating/stripping.
• Demonstrated extended cyclability (>500 cycles at 1C in coin cells, 92% retention after 300 cycles at 0.5C in pouch cells) and high-rate capability (10C).
• An 8.5 Ah pouch cell achieved a practical specific energy of 553 Wh/kg at the cell level.

Conclusions:

• The developed Li-Zn alloy and Li3N-enriched CNT composite offers a promising strategy for robust and high-performance lithium metal anodes.
• This approach facilitates the realization of high-energy density and long-cycle-life lithium metal batteries.
• The engineered composite addresses key limitations in current lithium metal anode technology, paving the way for practical applications.