Three-dimensional nanostructured composite lithium soap fibers for constructing high-performance lithium metal anode interfacial layers

Abstract

Lithium metal batteries are regarded as promising energy storage devices due to their high theoretical capacity, low density, and low electrode potential. However, the high reactivity of lithium leads to side reactions with the electrolyte and dendritic growth which hinder their commercial application. In this study, a lithium metal anode material with a three-dimensional nanostructured interface was prepared through interfacial modification engineering. The linear flexible molecular chains of the chelating agent, which crosslink with lithium stearate, result in a highly entangled, strong, and flexible three-dimensional porous structure of composite lithium soap fibers. The strong electrostatic interaction between the terminal RCOO⁻ groups and Li⁺ attracts Li⁺ ions into the three-dimensional matrix, constructing a lithiophilic protective layer at the micron and nanoscale. This enhances the stability of the SEI layer and the Li⁺ transport rate. The large specific surface area and abundant pores provide more reaction sites for lithium deposition and stripping. The unique mesh-like molecular structure, with high liquid transport performance, regulates the distribution of the electrolyte and homogenizes the lithium ion flux, effectively suppressing dendritic growth. The Li@DA symmetrical coin cells exhibits a long-term cycling performance of over 6800 hours, and the full battery maintains a high capacity retention of 92.04% after 530 cycles at a 2C rate with a high loading of 12 mg cm⁻². This three-dimensional nanostructured interfacial layer holds great potential for advancing the development of high-performance lithium batteries.