Synthesis and electrochemical performance of bud-like FeS2 microspheres as anode materials for rechargeable lithium batteries

Bud-like FeS2 powder was synthesized by a solvothermal method with the help of polyvinylpyrrolidone (PVP). The bud-like FeS2 microshperes with the diameters of 2.0–3.0 μm were consisted of the submicro-flakes with 0.5–1μm in width and length, and about 60 nm in thickness. As an anode material for Li-ion batteries, the bud-like FeS2 delivered initial specific discharge capacity of 773 and 749 mAh g−1, and could sustain 387 and 368 mAh g−1 after 30 cycles at current densities of 45 and 89 mA g−1, respectively, much higher than the solid one obtained without PVP. The bud-like FeS2 microshperes also showed large diffusion coefficient of Li-ions ( D Li + ) calculated by Galvanostatic intermittent titration (GITT). The improved electrochemical performance of bud-like FeS2 was due to the unique structure which provides large contact area between the FeS2 microspheres and electrolyte, decreased polarization and large D Li + , leading to enhanced electrode reaction kinetics.