Flexible Porous Silicon/Carbon Fiber Anode for High-Performance Lithium-Ion Batteries.

We demonstrate a cross-linked, 3D conductive network structure, porous silicon@carbon nanofiber (P-Si@CNF) anode by magnesium thermal reduction (MR) and the electrospinning methods. The P-Si thermally reduced from silica (SiO2) preserved the monodisperse spheric morphology which can effectively achieve good dispersion in the carbon matrix. The mesoporous structure of P-Si and internal nanopores can effectively relieve the volume expansion to ensure the structure integrity, and its high specific surface area enhances the multi-position electrical contact with the carbon material to improve the conductivity. Additionally, the electrospun CNFs exhibited 3D conductive frameworks that provide pathways for rapid electron/ion diffusion. Through the structural design, key basic scientific problems such as electron/ion transport and the process of lithiation/delithiation can be solved to enhance the cyclic stability. As expected, the P-Si@CNFs showed a high capacity of 907.3 mAh g-1 after 100 cycles at a current density of 100 mA g-1 and excellent cycling performance, with 625.6 mAh g-1 maintained even after 300 cycles. This work develops an alternative approach to solve the key problem of Si nanoparticles' uneven dispersion in a carbon matrix.

The Positive Effect of ZnS in Waste Tire Carbon as Anode for Lithium-Ion Batteries.

There is great demand for high-performance, low-cost electrode materials for anodes of lithium-ion batteries (LIBs). Herein, we report the recovery of carbon materials by treating waste tire rubber via a facile one-step carbonization process. Electrochemical studies revealed that the waste tire carbon anode had a higher reversible capacity than that of commercial graphite and shows the positive effect of ZnS in the waste tire carbon. When used as the anode for LIBs, waste tire carbon shows a high specific capacity of 510.6 mAh·g-1 at 100 mA·g-1 with almost 97% capacity retention after 100 cycles. Even at a high rate of 1 A·g-1, the carbon electrode presents an excellent cyclic capability of 255.1 mAh·g-1 after 3000 cycles. This high-performance carbon material has many potential applications in LIBs and provide an alternative avenue for the recycling of waste tires.

Facile and Scalable Approach To Fabricate Granadilla-like Porous-Structured Silicon-Based Anode for Lithium Ion Batteries.

A porous silicon and carbon composite (PSi/C) with granadilla-like structure as an anode material for lithium-ion batteries has been easily fabricated by spray drying and subsequent pyrolysis treatments. For the PSi/C, yolk-shell-structured Si/C nanobeads are equably distributed inside the porous carbon framework. The key point of this work is the combination of the advantages of both the yolk-shell structure and porous structure in one system. The void space inside the yolk-shell Si/C nanobeads and the interconnected three-dimensional porous carbon frameworks can effectively enhance the cyclic stability and conductivity of this composite. As expected, PSi/C with 15.4% silicon content exhibited a specific capacity as high as 1357.43 mAh g-1 and retained 933.62 mAh g-1 beyond 100 cycles at 100 mA g-1. Moreover, it showed a reversible specific capacity as high as 610.38 mAh g-1 at 1000 mA g-1, even after 3000 cycles.