Mass production of three-dimensional hierarchical microfibers constructed from silicon-carbon core-shell architectures with high-performance lithium storage
In this work, a facile approach is reported to mass produce highly porous fibers constructed from silicon-carbon core-shell structures. The C-Si microfibers are prepared using a modified electrospinning deposition method (ESD), and subsequent calcination of the carbon shells. Benefited from the step of vacuum drying, the unnecessary solvent left in the precursor will volatilize, resulting in the uniform three-dimensional hierarchical microfibers constructed from silicon-carbon core-shell architectures. The uniform covering layers of carbon formed by decomposition of polymer contribute to the improvement of conductivity and alleviation of volume change. The pores in the microfibers are helpful for the diffusion of electrolyte. When evaluated as an anode material for lithium-ion batteries, the C-Si microfibers exhibit improved reversibility and cycling performance compared with the commercial Si nanoparticles. A high capacity of 860 mAh g(-1) can be retained after 200 cycles at a current rate of 0.3 C. The rate capability of the C-Si microfibers is also improved. The special structure is believed to offer better structural stability upon prolonged cycling and to improve the conductivity of the material. This simple strategy using the modified ESD method could also be applied to prepare other porous energy materials.