Surfactant-assisted RGO limited spherical FeS with superior stability and high capacity as an anode for lithium-ion batteries

The realization of high cycling stability and high reversible capacity of lithium-ion storage is the critical factor to promote the development of lithium-ion batteries. Here, a composite of spherical FeS particles distributed on the surface of graphene (FeS/rGO-60) has been designed by cetyltrimethylammonium bromide (CTAB)-assisted synthesis. The surface of graphene is activated by the surface activity of CTAB so that it can better anchor FeS. In the FeS/rGO-60 composite, spherical FeS particles of about 1 μm are uniformly distributed on the graphene surface, and no agglomeration occurs, thus resulting in excellent electrochemical properties. As a candidate anode, FeS/rGO-60 composite electrode exhibits ultra-high specific capacity and excellent cycling stability (1300 mAh g−1 over 1100 cycles at 1 A g−1), superior to those FeS-based anode materials reported so far. Even at higher current densities of 5 A g−1, the resulting electrode still maintains a high capacity of 432.9 mAh g−1 and its initial morphology after 900 cycles, confirming its superior rate performance and stability. The LiFePO4//FeS/rGO-60 full cell showed a high energy density of 797 Wh kg−1 at a power density of 824.2 W kg−1. At a 0.5 A g−1, the LiFePO4//FeS/rGO-60 full battery exhibited a remarkable cycling capacity with 488.6 mAh g−1 after 80 cycles. The creative idea in this work provides a new way to construct stable metal sulfide/rGO composite electrode materials for high Lithium storage performance.