Smart construction of polyaniline shell on Fe2O3 as enabling high performance anode toward flexible lithium-ion battery

Abstract

A novel Fe₂O₃@CC (carbon cloth) composite, encapsulated in a polyaniline (PANI) shell and further enhanced by nitrogen doping, is developed to form a core–shell structure. The carbon framework provides robust electrical conductivity, while the nitrogen doping introduces additional active sites for lithium-ion interaction and improves electrochemical performance. This flexible electrode design not only enhances ion diffusion but also delivers structural integrity, making it highly suitable for high-performance energy storage applications. The flexible properties of PANI effectively adapt to the volume change of Fe₂O₃ during the cycling process. The assembled battery Fe₂O₃@CC-PANI-30 core–shell nanowire arrays provides a capacity of 768.5 mA h g⁻¹ after 100 cycles at 100 mA g⁻¹. Even after 800 cycles at 500 mA g⁻¹, it provides 468.3 mA h g⁻¹ capacity. The N-doped PANI layer not only improves conductivity but also alleviates the volume expansion of Fe₂O₃ during charge–discharge processes, reducing mechanical stress and enhancing cycling stability. Notably, the PANI coating, enriched with N heteroatoms, introduces numerous defects that create ample channels for efficient Li⁺ transport. This synthetic approach, leveraging nitrogen doping to boost both electronic and ionic conductivity, provides valuable insights for designing integrated flexible electrodes, offering a significant improvement over Fe₂O₃ and Fe₂O₃@CC systems without nitrogen modification.