High-capacity rechargeable batteries based on deeply cyclable lithium metal anodes

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Lithium metal anodes offer high theoretical capacity but suffer from low efficiency and dendrite formation, limiting their practical application.
• Current strategies to improve lithium metal electrodes are often confined to shallow cycling conditions with poor utilization.
• Developing stable and efficient deep-cycling lithium metal anodes is critical for next-generation high-energy-density batteries.

Purpose of the Study:

• To achieve highly reversible and stable deep cycling of lithium metal anodes at high capacities.
• To investigate the mechanism behind the improved performance of lithium metal electrodes.
• To construct and evaluate a full battery cell utilizing the developed lithium metal anode.

Main Methods:

• Fabrication of lithium metal electrodes designed for deep cycling.
• Electrochemical cycling and performance evaluation in a commercial LiPF6/carbonate electrolyte.
• Analysis of the protective layer formed on the lithium metal surface using advanced techniques.
• Construction and testing of a Li-MoS3 full cell.

Main Results:

• Demonstrated deep cycling of lithium metal electrodes at 10 and 20 mAh cm-2 with average Coulombic efficiency >98%.
• Identified a protective layer composed of Li3N and lithium oxynitrides (LiN O y) formed via LiNO3 decomposition, enabling dendrite-free deposition.
• Constructed a Li-MoS3 full cell that significantly outperforms existing laboratory cells and commercial lithium-ion batteries.

Conclusions:

• The developed lithium metal anode enables stable and efficient deep cycling, overcoming key limitations of lithium metal batteries.
• The in-situ formed protective layer is crucial for reversible lithium deposition and long cycle life.
• This advancement paves the way for high-capacity and high-energy-density rechargeable batteries exceeding current market standards.