Metal-organic framework derived flower-like FeS/C composite as an anode material in lithium-ion and sodium-ion batteries

Among all the metal sulfides, iron sulfide (FeS) possesses the advantages of low-cost, environmentally-sound, and with high capacity. However, the large volume expansion during the electrochemical reaction process and the poor electrical conductivity limit its further application. In this work, flower-like FeS/C derived from metal-organic framework material was first synthesized through dopamine coating, hydrothermal sulfurization and thermal reduction methods. In the composite, FeS nanoparticles and carbon were compounded together and formed a stable laminated structure, and the FeS nanoparticles were encapsulated by carbon. FeS/C composites with different contents of dopamine coating showed different morphologies. Among the composite electrodes, FeS/C-2 electrode exhibited the best electrochemical performance. When tested for half-cells in LIBs, the FeS/C-2 electrode exhibited an initial discharge capacity of 994.4 mAh.g(-1) at the current density of 0.1 A g(-1), and with a capacity retention of about 77.3% after 100 cycles. When tested for half-cells in SIBs, the initial discharge capacities of the composite electrode were as high as 809.7 and 403.2 mAh.g(-1), at a current density of 1 and 4 A g(-1), respectively. In the carbon wrapped FeS composite with laminated structure, the path ways of the electrons and ions were shortened; moreover, the volume expansion of FeS was also restrained by carbon. (C) 2019 Elsevier B.V. All rights reserved.