Electrochemical stability of electrospun silicon/carbon nanofiber anode materials: a review

Silicon (Si) is regarded as a promising anode material owing to its high specific capacity and low lithiation potential. The large volume change and the pulverization of silicon during the lithiation/delithiation process hinder its direct energy storage application. This review focuses on the electrospun silicon/carbon (Si/C) nanofiber anode materials for lithium-ion batteries for long-term stable energy storage. Silicon is completely embedded in electrospinning-based carbon nanofibers to form electrospun Si/C nanofibers. It not only creates pore space to buffer silicon volume expansion, but also prevents direct contact between silicon and the electrolyte, consequently forming a stable solid electrolyte interface film. The electrospun Si/C nanofibers solve the pulverization issue of silicon to achieve improved cycling stability. Furthermore, the electrospun carbon nanofibers form a flexible conductive network for surrounding silicon by facilely introducing sacrificial polymers or template agents. The electrospun Si/C nanofibers ultimately promote the lithium-ion transport to achieve rate stability. The silicon source selection and microstructure regulation of the electrospun Si/C nanofibers are overviewed. The silicon sources include the direct utilization of silicon or silicon oxide particles as well as the indirect conversion of silicon-based precursors. The cycling stability regulation of various metal- and metal oxide-modified silicon composites and heterogeneous carbon material-decorated electrospun Si/C nanofibers is summarized. In addition, the microstructure designs of the electrospun Si/C nanofibers associated with the improvement of long-term capacity retention are overviewed. The main challenges in the electrospun Si/C nanofiber anode materials are summarized, and the future perspectives are also proposed.