Polypyrrole-coated triple-layer yolk–shell Fe₂O₃ anode materials with their superior overall performance in lithium-ion batteries

Iron oxide (Fe₂O₃) emerges as a highly attractive anode candidate among rapidly expanding energy storage market. Nonetheless, its considerable volume changes during cycling as an electrode material result in a vast reduced battery cycle life. In this work, an approach is pioneered for preparing high-performance Fe₂O₃ anode materials, by innovatively synthesizing a triple-layer yolk–shell Fe₂O₃ uniformly coated with a conductive polypyrrole (Ppy) layer (Fe₂O₃@Ppy-TLY). The uniform polypyrrole coating introduces more reaction sites and adsorption sites, and maintains structure stability through charge-discharge process. In the uses as lithium-ion battery electrodes, Fe₂O₃@Ppy-TLY demonstrates high reversible specific capacity (maintaining a discharge capacity of 1375.11 mAh·g⁻¹ after 500 cycles at 1 C), exceptional cycling stability (retaining the steady charge-discharge performance at 544.33 mAh·g⁻¹ after 6000 ultrafast charge-discharge cycles at a 10 C current density), and outstanding high current charge-discharge performance (retaining a reversible capacity of 156.75 mAh·g⁻¹ after 10000 cycles at 15 C), thereby exhibiting superior lithium storage performance. This work introduces innovative advancements for Fe₂O₃ anode design, aiming to enhance its performance in energy storage fields.