Synthetic Strategy of Si@void@C Nanoparticles for High- Performance Lithium-Ion Battery Anodes

Silicon anode materials have the absolute predom-inance of high theoretical specific capacity, but its conductivity is low. What is more, the huge volume expansion (similar to 300%) of silicon during cycling causes rapid capacity fading. Herein, high-perform-ance Si@void@C nanoparticles are synthesized by a unique ZnO template and mild strategy for the first time. Compared with the traditional synthesis method, a milder and environmentally friendly synthesis strategy provides a new feasible scheme for the large-scale commercialization of silicon anodes. The carbon layer blocks the silicon from the electrolyte and improves the conductivity of materials, and the yolk-void-shell structure accommodates the volume expansion of silicon during cycling. Si@void@C nanoparticles prepared with the ZnO template show excellent cycle and rate performances compared with the traditional synthetic strategy. After 500 cycles, the specific capacity of Si@void@C still maintains 934 mA h g-1 at 1 A g-1, and the average specific capacity is as high as 1125.4 mA h g-1 at a high current density of 4 A g-1. To sum up, the potential of Si@void@C anode for lithium-ion batteries cannot be underestimated.

Automated summary

Si@void@C nanoparticles with a carbon layer and yolk-void-shell structure are successfully synthesized using a ZnO template and mild synthesis strategy. The carbon layer improves material conductivity and blocks silicon from the electrolyte, while the yolk-void-shell structure accommodates silicon volume expansion during cycling. Compared to traditional synthesis methods, these nanoparticles exhibit better cycle and rate performances.