Self-supporting N, P doped Si/CNTs/CNFs composites with fiber network for high-performance lithium-ion batteries

Abstract

Silicon (Si) with high theoretical capacity has attracted much attention as anode materials of lithium-ion batteries (LIBs). However, the tendency of Si particles to easily expand leads to the rapid attenuation of capacity, which greatly limits their practical applications. In this work, the nitrogen (N) and phosphorus (P) doped Si/CNTs carbon nanofibers (Si/CNTs/CNFs) composites has been fabricated and explored as electrode material for LIBs. N, P doped Si/CNTs/CNFs composites possess unique fiber network structure with suitable space, which can effective buffer volume expand during charge-discharge process. By evaluating lithium storage performances of N, P doped Si/CNTs/CNFs composites as Li-ion battery electrodes, excellent rate performance with a capacity of 529 mA h g−1 (at 5.0 A g−1) and remarkable cycling performance of 1142 m Ah g−1 after the 100 cycles (at 0.2 A g−1) are obtained. Such outstanding performances can be attributed to the unique fiber network structure and the doping of N and P, which provides a new avenue for the studies of high-performance Si based anode materials of LIBs.