Lithiophilic Sn layer via pre-electroplating to realize the uniform stripping/ plating for dendrite free Li metal anodes

Lithium (Li) metal is expected to become the next generation anodes materials, owning to the irreplaceable advantages (high the theoretical specific capacity, high energy density, and low electrochemical potential). However, the huge volume exchange and dendritic Li growth hinder its development. In this paper, a recyclable method was put forward to relief the above issues for achieving stable Li metal anodes, where the uniform Sn layer was built on the surface of copper foam (SCF) by pre-electroplating. The porous structure of copper foam (CF) can accommodate deposited Li to relax the huge volume change. The Sn layer of SCF improves the lithiophilicity of structure, preventing the inhomogeneous deposition by the tip effect. In view of the synergies of porous structure and lithiophilic Sn layer, the SCF shows good compatibility with Li metal anodes. During the preparation process of SCF, the electroplating solution is recyclable and the cost of energy is low, which prevents environmental pollution and resembles the initial target of secondary energy storage. Meanwhile, the symmetrical cells of SCF show longer life than CF and copper foil. After 550 cycles, the coulomb efficiency of SCF can be stable more than 98 % at 1 mA cm-2 with 1 mAh cm-2. The full cells of LFP||Li@SCF deliver satisfactory capacity (117.1 mAh/g) at 1C after 130 cycles. With further research, the pre-electroplating has the potential to be another way for the building of framework structure in the field of Li metal anodes.

Automated summary

This study proposes a recyclable method for achieving stable lithium metal anodes by pre-electroplating a uniform tin layer on the surface of copper foam. The porous structure of the copper foam can accommodate deposited lithium and alleviate volume changes. The tin layer improves the lithiophilicity of the structure, preventing inhomogeneous deposition. The results demonstrate good compatibility and longer lifespan of the material.