High Rate Capacity Anode of Si-C Composite Nanofiber Wrapped with Cu Foam for Lithium-ion Batteries

Abstract To resolve the huge volume expansion and poor electronic conductivity of silicon anode which restricts the cycling stability and rate capacity of lithium-ion batteries, a novel structure of copper foam wrapped silicon/carbon nanofibers (Si/CNFs-Cu) is successfully fabricated and applied as anode material in lithium ion battery. It exhibits excellent rate performance of 565.2 mAh g−1 at a high current density of 5 A g−1 and high cycling stability with the retention rate of 66.7% after 80 cycles at 0.5 A g−1. The rate capacity is as 2.8 times as Si/CNFs and it is attributed to the framework structure of Si/CNFs-Cu which insures the faster electron transfer along the thickness direction of the anode material in charging/discharging processes. Furthermore, the complete wrapped electrode structure can avoid the separation of the composite fibers from the electrode during cycling substantially.