Flexible binder-free silicon/silica/carbon nanofiber composites as anode for lithium–ion batteries

• Flexible Si/SiO2/C composite nanofibers were introduced as Li–ion battery anodes.
• SiO2 component of composite nanofibers facilitated the high flexibility.
• Flexible Si/SiO2/C composite nanofibers were coated with CVD-carbon.
• CVD carbon coating and SiO2 component led to high capacity retention.

High-capacity flexible electrode materials for high-energy lithium–ion batteries become critically important with technological improvements on portable and bendable electronic equipment such as rollup displays, implantable medical devices, active radio-frequency identification tags, and wearable devices. Although different types of bendable electrode materials have been introduced, it is very important to fabricate highly-flexible electrode materials with reasonable fabrication technique and high electrochemical performance similar to those of conventional high-capacity electrode materials. Herein, we introduced high-capacity, flexible Si/SiO2/C nanofiber composite anode materials by simple electrospinning and subsequent heat treatment processes. To further improve the long-term cycling performance, additional nanoscale carbon coating of flexible Si/SiO2/C nanofibers was performed by CVD technique. Electrochemical performance results showed that CVD carbon-coated flexible Si/SiO2/C nanofiber composites exhibited high capacity retention of 86.7% and high coulombic efficiency of 96.7% at the 50th cycle. It is, therefore, demonstrated that CVD carbon-coated flexible Si/SiO2/C nanofiber composites are promising anode material candidate for next-generation flexible and high-energy lithium–ion batteries.

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