Facile synthesis of Fe3S4 microspheres as advanced anode materials for alkaline iron-based rechargeable batteries

A new kind of spherical Fe 3 S 4 with a 3D hierarchical structure, which is constructed with many intercrossed nanorods , is successfully synthesized via a facile hydrothermal method . The achieved Fe 3 S 4 microspheres are evaluated as advanced anode materials for alkaline iron-based secondary batteries for the first time. Influences of hydrothermal temperature on the physical and electrochemical performances of Fe 3 S 4 particles are investigated systematically. It is found that the Fe 3 S 4 fabricated at 150 °C exhibits better electrochemical properties than the ones obtained at other temperatures, including higher discharge capacity, attractive high-rate capability and good cycling stability. At 0.2, 0.4, 1.0, 2.0, and 5.0 C, the Fe 3 S 4 (150 °C) delivers discharge capacity of ~328.5, ~307.6, ~280.5, ~235.9, and ~169.5 mAh g −1 , respectively. Especially, after 400 cycles at 1 C/1 C, the Fe 3 S 4 (150 °C) presents capacity retention of 88.61%. The pronounced performance of Fe 3 S 4 is attributable to its inherent electrochemical activity, unique 3D hierarchical structure, and high S content, eventually resulting in the reduced charge transfer resistance, improved reversibility, and a beneficial porous electrode structure during cycling. Therefore, the as-achieved Fe 3 S 4 microspheres are promising anode materials for high-performance alkaline iron-based batteries.