Self-assembled cauliflower-like FeS2 anchored into graphene foam as free-standing anode for high-performance lithium-ion batteries

For the first time, self-assembled cauliflower-like FeS2 anchored into three-dimensional graphene foams (3DGF-FeS2) are synthesized by one-pot hydrothermal method. Without polymeric binders, conductive additives, or metallic current collectors, the 3DGF-FeS2 composite can be directly used as freestanding and binder-free anode for lithium-ion batteries (LIBs), which demonstrates pronounced electrochemical performance: it exhibits a large initial capacity of 1251.3 mAh g−1 and remains 1080.3 mAh g−1 after 100 cycles at 0.2 C, which is much higher than the theoretical capacity (890 mAh g−1) of bare FeS2 bulk material; it delivers excellent high-rate performance with a capacity of 615.1 mAh g−1 even at 5 A g−1. The pronounced enhancement in electrochemical performance is mainly attributed to the synergistic effect of 3DGF matrix and the unique self-assembly architecture. The porous and conductive 3DGF network offers efficient channels for electron transfer and ionic diffusion and the self-assembled cauliflower-like architecture restrains the aggregation of FeS2 and enhance the stability of 3DGF-FeS2 by suppressing the volume expansion during cycling processes. The 3DGF-FeS2 is promising as superior-capacity free-standing and binder-free anode for LIBs.

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