One-Step Synthesis of Multi-Core-Void@Shell Structured Silicon Anode for High-Performance Lithium-Ion Batteries

The core-void@shell architecture shows great advantages in enhancing cycling stability and high-rate performance of Si-based anodes. However, it is usually synthesized by template methods which are complex and environmentally unfriendly and would lead to low-efficiency charge and mass exchange because of the single-point van der Waals contact between the Si core and the shell. Here, a facile and benign one-step method to synthesize multi-Si-void@SiO2 structure, where abundant void spaces exist between multiple Si cores that are multi-point attached to a SiO2 shell through strong chemical bonding, is reported. The corresponding electrode exhibits highly stable cycling stability and excellent electrochemical performance. After 200 cycles at a current density of 0.1 A g(-1) and then another 200 cycles at 1.2 A g(-1), the electrode outputs a specific capacity of 1440 mAh g(-1). Even at 2.0 A g(-1), it outputs a specific capacity as high as 1182 mAh g(-1). Such an anode can match almost all the cathode materials presently used in lithium-ion batteries. These results demonstrate the multi-Si-void@SiO2 as a promising anode to be used in future commercial lithium-ion batteries of high energy density and high power density.