Crystalline/Non-Crystalline Carbon Co-Modified Strategy to Construct N, S Co-Doped Carbon Layer Wrapped Fe0.95S1.05/Carbon Nanotubes for Enhanced Lithium Storage Property

Abstract

Due to their high theoretical capacity and abundant resources, transition metal sulfides are regarded as a prospering alternative to replace the commercial graphite anode in lithium-ion batteries (LIBs), particularly for large-scale energy storage and conversion applications. Nonetheless, low conductivity, easy agglomeration and obvious volume change greatly impede their practical application. In this work, a novel crystalline/non-crystalline carbon co-modified strategy is proposed to fabricate N, S co-doped carbon (NSC) layer wrapped Fe_0.95S_1.05/carbon nanotubes (CNTs) composite (Fe_0.95S_1.05/CNTs@NSC) through a simple Fenton reaction followed by a sulfurization process. Systematical characterizations and analyses reveal that this strategy well combines the advantages of crystalline CNTs and non-crystalline NSC, ensuring good conductivity and a high contribution to capacity from the carbon matrix. Meanwhile, the joint encapsulation of Fe_0.95S_1.05 by both CNTs and NSC can significantly mitigate the agglomeration and volume change of Fe_0.95S_1.05 during the continuous charge/discharge process. Benefiting from these advantageous features, the resultant Fe_0.95S_1.05/CNTs@NSC composite displays much improved cycling stability and rate capability when compared to the counterparts. Clearly, our research offers a distinct and innovative approach to design and construct advanced transition metal sulfides/carbon composite anodes for LIBs.