Facile Fabrication of Si/Ge/G@C Composite Electrodes for High Performance Lithium-ion Batteries

Silicon has been considered as one of the most promising anode materials due to its ultra-high specific capacity and moderate operating voltage. However, the huge volume variation and poor electronic conductivity that hindered its further practical applications. Preparing composite materials that combine multi-type advantages is an effective approach. Herein, a silicon/germanium/graphite@amorphous carbon (Si/Ge/G@C) composite anode material that combines the advantages of Si, Ge and carbon materials was prepared via a simple ball milling and high temperature annealing method, which exhibit a porous structure. The synergistic effect of Si, Ge, and carbon materials plays an important role in the composite, where Si and Ge both have high specific capacity, Ge improves the electronic conductivity, and carbon accelerates the electron transfer and effectively buffers the volume variation after lithiation and delithiation. As expected, the Si/Ge/G@C composite electrode exhibited excellent cycling stability with an initial discharge specific capacity of 1165.2 mAh g(-1) and a high reversible capacity of 706.0 mAh g(-1) after 100 cycles. At the same time, the good rate performance can be observed under different current densities from 100 to 600 mA g(-1). The EIS results of the Si/Ge/G@C composite electrode suggest the formation of stable SEI layer on electrodes. This work demonstrates a facile and cost-effective approach to prepare high performance electrode with multi-type advantages for lithium ion batteries. The electrode with high specific capacity, good electronic conductivity and enhanced cycling stability was obtained by simple composite method. This research provides a new perspective for the mass production of high-performance LIB anodes for applications.

Automated summary

In this study, a silicon/germanium/graphite@amorphous carbon composite anode material was prepared, which combines the advantages of silicon, germanium, and carbon materials. The composite electrode exhibited high specific capacity, good electronic conductivity, and enhanced cycling stability, making it a promising candidate for lithium-ion batteries.