Facile Preparation Of Nitrogen-Doped Yolk-Shell Si@Void@C/Cnts Microspheres As High-Performance Anode In Lithium-Ion Batteries

Commercialization of silicon (Si) anodes remains a significant challenge due to their severe volume change and low intrinsic conductivity during cycling. To address the limitations, we herein report a facile strategy to design and prepare nitrogen-doped yolk-shell Si@void@C/CNTs microspheres via spray drying followed by carbonization and etching procedure. In the resulting architecture, the constructed void could act as a volumetric expansion-relieved space, which not only provides a buffer area for adapting the volume expansion of Si nanoparticles, but also significantly facilitates ions transport and offers more ion-accessible area upon cycling. The randomly interlinked carbon nanotubes (CNTs) networks, together with the N-rich amorphous carbon matrix cooperatively provide fast electron transport pathways and high electrical conductivity. Benefitting from the synergistic features, Si@void@C/CNTs anode exhibits a high discharge capacity of 1034 mA h/g at 200 mA/g after 500 cycles, and stable cycling performance with a reversible capacity of 680 mA h/g at 500 mA/g after 500 cycles, and superior rate capability of 204 mA h/g at 4 A/g. The novel approach proposed for Si anodes demonstrates promising prospects in developing high-capacity anode materials for next-generation lithium-ion batteries.