Carbon-coated Si/N-doped porous carbon nanofibre derived from metal–organic frameworks for Li-ion battery anodes

• Sandwich structure of carbon-coated Si/N-doped porous carbon fibre were prepared. • The porous fibre and sandwich structure provide support for volume change of Si. • Excellent rate capacity and cycling performance. In order to more effectively alleviate the volume extension and shrinkage of the Si anode during Li intercalation/deintercalation processes, and also to improve the electron and ion transport dynamics, carbon coated Si-porous carbon composite fibres with a sandwich structure were prepared using a sacrificial template (ZIF-8) to construct mesoporous carbon, combined with electrospinning technology and subsequent hydrothermal carbon coating. The carbon fibre skeleton and carbon-coated sandwich structure provide support for the volume extension and shrinkage of Si, avoiding Si from directly contacting with the electrolyte, and forming a stable solid electrolyte interphase film. Furthermore, the polyvinylpyrrolidone spinning solution assists ZIF-8 to obtain a mesoporous structure inside the carbon fibre, which improves the specific surface area and pore volume of the composite material. In this case, the mesoporous structure also helps to alleviate the volume extension and shrinkage of Si during the charging /discharging processes and improves the transmission dynamics of lithium ions and electrons. Benefit from the unique structural features, this anode composite material exhibits enhanced electrochemical properties for Li-ion batteries, with a reversible specific capacity of 1114 mAh g −1 at 1 A g −1 , and demonstrates a capacity retention rate of 66% with a specific capacity of 740 mAh g −1 after 400 cycles.