An Advanced Design Concept of Mansion-like Freestanding Silicon Anodes with Improved Lithium Storage Performances

To conquer inherently low conductivity, volume swelling, and labile solid electrolyte interphase (SEI) films of Si anode in lithium ion battery (LIBs), it is widely accepted that appropriate structure design of Si-C hybrids performs effectively, especially for nanosize Si particles. Herein, inspired by the sturdy construction of high-rise buildings, a mansion-like 3D structured Si@SiO2/PBC/RGO (SSPBG) with separated rooms is developed based on 0D core-shell Si@SiO2, 1D pyrolytic bacterial cellulose (PBC) and 2D reduced graphene oxide (RGO). Therefore, these hierarchical protectors operate synergistically to inhibit the inevitable volume changes during electrochemical process. Specifically, tightly coated SiO2 shell as the first protective layer could buffer the volume expansion and reduce detrimental pulverization of Si NPs. Furthermore, flexible spring-like PBC and ultra-fine RGO sheets perform as securer barriers and skeleton which will counteract the microstructure strain and accelerate electron transfer at the same time. Remarkably, the self-supporting electrode realizes a distinguished performance of 901 mAh g(-1) at 2 A g(-1) for 500 cycles. When matched with LiFePO4 cathodes, high stability of more than 100 cycles has been realized for the full batteries.

Automated summary

Inspired by high-rise buildings, a 3D structured Si@SiO2/PBC/RGO material has been developed to address the challenges of Si anodes in lithium ion batteries. This structure demonstrates excellent electrochemical performance and stability.