High-Coulombic-Efficiency Carbon/Li Clusters Composite Anode without Precycling or Prelithiation

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium metal anodes are crucial for high-energy-density lithium-ion batteries.
• Challenges include uncontrollable deposition, volume expansion, and dendrite formation, hindering practical application.

Purpose of the Study:

• To investigate a novel metastable state of lithium (Li) that forms during the over-lithiation of carbon cloth (CC).
• To evaluate the performance of a composite anode utilizing these Li clusters for lithium-ion batteries.

Main Methods:

• Over-lithiation of carbon cloth (CC) to induce the formation of Li clusters.
• Electrochemical characterization of the CC/Li clusters composite anode in half-cells.
• Assembly and testing of full cells using the CC/Li clusters composite anode.

Main Results:

• Discovery of metastable Li clusters (micrometer and submicrometer scale) with excellent electrochemical reversibility.
• CC/Li clusters composite anode achieved a high first-cycle coulombic efficiency (CE) of 94.5% ± 1.0% and a stable CE of 99.9% over 160 cycles.
• Demonstrated high capacity (3 mAh cm⁻²) and stable cycling with a sloping voltage profile; full cells showed good performance over 200 cycles without precycling.

Conclusions:

• Metastable Li clusters offer a viable solution to lithium metal anode instability.
• The CC/Li clusters composite anode provides a promising pathway for developing high-energy-density and stable lithium-ion batteries.
• This controlled formation of Li clusters simplifies battery assembly and enhances overall performance.