A Sandwich CNTs-Si-CNTs Current Collector Enabling Uniform Lithium Plating for Anode-Free Lithium Metal Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Anode-free lithium metal batteries (AFLBs) promise high energy density but suffer from lithium dendrite growth and unstable solid electrolyte interphase (SEI) formation.
• Current 3D hosts often exhibit non-uniform lithium deposition, limiting their effectiveness in AFLBs.

Purpose of the Study:

• To develop a novel current collector for AFLBs that promotes uniform lithium deposition and enhances battery performance.
• To investigate the effect of embedded silicon (Si) lithiophilic sites within a carbon nanotube (CNT) network on lithium plating behavior.

Main Methods:

• Fabrication of a sandwich CNT-Si-CNT current collector using gradient vacuum filtration.
• Evaluation of lithium plating/stripping using Li half-cell, symmetric-cell, and LiFePO4 (LFP) full-cell configurations.
• Characterization of electrochemical performance, including Coulombic efficiency, cycling stability, and polarization.

Main Results:

• The optimized 5Si-CNTs current collector significantly reduced lithium nucleation overpotential to 21.3 mV.
• Achieved an average Coulombic efficiency of 90.53% over 100 cycles at 1 mA cm⁻².
• Demonstrated stable symmetric-cell cycling for 210 hours at 0.25 mA cm⁻² with low polarization and improved LFP full-cell discharge capacity retention.

Conclusions:

• Embedding lithiophilic Si sites within a CNT scaffold provides a practical strategy for uniform lithium plating in AFLBs.
• The developed CNT-Si-CNT current collector enhances reversibility and stability, addressing key challenges in AFLB technology.
• This approach offers a promising route towards realizing high-performance and long-lasting anode-free lithium metal batteries.