A flexible micro/nanostructured Si microsphere cross-linked by highly-elastic carbon nanotubes toward enhanced lithium ion battery anodes

Inspired by the carbon nanotubes (CNTs) with high elasticity, we design a flexible conductive Si/CNT composite where the CNTs are in situ grown in the porous Si particles with mesoscale porosity to solve the problems facing high capacity Si-based anodes. The Si/CNT composite with CNTs in situ grown into the Si wall and mesoscale porosity has advantages in several aspects, including improving the electron transport within the Si particle, holding the Si domains together without getting pulverized, and exhibiting excellent mechanical properties. As a result, the as-obtained Si/CNT composites delivers a reversible capacity of 1275.5 mA h g(-1) at 0.2 A g(-1) after 100 cycles and a capacity of 715.5 mA h g(-1) at 1 A g(-1) after 400 cycles. When assembled with the Si/CNT composite as anode and commercial LiCoO2 as cathode, the full cell delivers a reversible capacity of 127.4 mA h g(-1) with a working potential beyond 3.0 V based on the cathode active material. The enhanced performance could be attributed to the flexible conductive microstructured design, which can significantly improve conductivity, stabilize SEI film, and maintain the integrity of the porous Si-based electrodes.