Hierarchical carbon-coated Fe1-xS/mesocarbon microbeads composite as high-performance lithium-ion batteries anode

Iron sulfide is considered as a promising anode material for lithium ion batteries because of its high theoretical capacity, low price and non-toxicity. Unfortunately, the inherent disadvantages of iron sulfide limit its practical application, such as, low electrical conductivity, volume expansion and polysulfide dissolution during charge and discharge. Herein, a hierarchical carbon-coated Fe1-xS/mesocarbon microbeads (Fe1-xS@C/MCMB) composite with excellent cycle stability and high-rate performance was synthesized by a facile one-step in situ thermal condensation method. In this composite, the MCMB core and the external amorphous carbon provide a buffer matrix and construct a three-dimensional conducive network around the Fe1-xS nanoparticles. In addition, amorphous carbon can also act as a protective film to increase the bonding strength between MCMB and Fe1-xS nanoparticles, and inhibit the shuttle effect of polysulfide. The Fe1-xS@C/MCMB composite as lithium-ion batteries anode material exhibited excellent cycle stability (capacity retention: 531.7 mAh g at 200 mA g(-1) over 120 cycles) and high-rate performance (with a reversible capacity of 253 mAh g(-1) even at 2 A g(-1)). The design of the novel structure is expected to promote the development of commercial metal sulfide-based anode materials with impressive cycle stability.