Mild strategy for generating rich void space for nano-Si/C composites to accommodate the large volume expansion during alloying/dealloying for lithium-ion batteries

Silicon-based materials are promising high-capacity anodes for lithium-ion batteries (LIBs). However, they suffer from rapid fracture and pulverization due to extreme volume expansion (theoretically higher than 300%) during the alloying/dealloying reactions with Li. In this work, we demonstrated a simple and mild method by using calcium carbonate as the template to prepare a Si/carbon-based anode material with rich void space (Si@void@C) for LIBs. The yielded void space successfully accommodated the large volume change during the cycling process. The electrochemical characterization verified that the Si@void@C anode exhibited an excellent specific capacity of 973.2 mA h g(-1) and high-capacity retention of 84.9% after 100 cycles at a current density of 300 mA g(-1). The morphological study also confirmed that the Si@void@C electrode exhibited the lowest volume changes after many cycles of the charge/discharge process among the electrodes. In addition, the comprehensive performance of Si@void@C was remarkably better than those of Si@C and bare Si electrodes. Hence, Si@void@C is a promising high-capacity anode for next-generation LIBs. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

Silicon-based materials have shown promise as high-capacity anodes for lithium-ion batteries, and a Si/carbon-based anode material with rich void space (Si@void@C) was prepared using calcium carbonate as a template in this study. The void space accommodated volume changes during cycling processes, leading to excellent specific capacity and high-capacity retention. The comprehensive performance of Si@void@C was significantly better than other electrodes, making it a promising high-capacity anode for next-generation LIBs.