High-performance, flexible, binder-free silicon–carbon anode for lithium storage applications

Abstract

The development of flexible Li-ion batteries (LiBs) is important for applications in wearable devices, display systems, intelligent communication, and other electronics fields. Herein, we report a flexible, binder-free, silicon@silica@carbon nanofiber (Si@SiO2@CNF) anode fabricated by a scalable electrospinning method and a novel “pre-oxidation–slicing–carbonization” process. Si nanoparticles (Si NPs) uniformly dispersed within the CNFs were coated with layers of SiO2, leading to the formation of core–shell-structured silicon@silica (Si@SiO2). Due to the introduction of the SiO2 coating, aggregation of the Si NPs was effectively inhibited, and the change in volume of the Si NPs could be confined within the CNFs during cycling, resulting in enhanced structural and cycling stability. Furthermore, the interconnected conductive CNFs further increased the overall conductivity, leading to improved rate performance. More importantly, the novel “pre-oxidation–slicing–carbonization” process ensures the integrity of the edge of the electrode film. The fiber film obtained by electrospinning can be used directly as a freestanding, binder-free anode material, which significantly simplifies the fabrication process and reduces the cost. The Si@SiO2@CNF composite retains excellent performance of 903.7 mAh g−1 beyond 100 cycles at 100 mA g−1, and a remarkable rate capacity of 634.6 mAh g−1 after 300 cycles. The proposed facile and scalable synthesis means that this novel, flexible, and binder-free Si/C anode should have practical applications in next-generation, flexible, binder-free Li-ion batteries.

Keywords

• Silicon
• Flexible
• Binder-free
• Anode
• Li-ion batteries