Resource utilization of iron ore concentrate leachate: Constructing polyacrylonitrile-coated Fe2O3 core-shell structures for optimized lithium storage performance

Iron oxide (Fe 2 O 3 ) has emerged as a potential anode candidate for next-generation lithium-ion batteries (LIBs), attributed to its considerable theoretical capacity and natural abundance. Nevertheless, its practical application is hindered by poor electrical conductivity and severe volume changes during cycling, which lead to rapid capacity fading and poor rate performance. This study presents a sustainable strategy for synthesizing high-performance Fe 2 O 3 -based anodes using iron ore leachate. Fe 2 O 3 @PAN core-shell composites are successfully fabricated via chemical precipitation–calcination, followed by in-situ polyacrylonitrile (PAN) coating and thermal cyclization. Structural characterization confirmed the formation of a uniform cyclized PAN shell that enhances both mechanical resilience and conductivity. Among the synthesized composites, Fe 2 O 3 @PAN-9 demonstrated the most balanced performance, delivering a high reversible capacity of 941.38 mAh g −1 after 200 cycles at 0.5 A g −1 and maintaining 619.12 mAh g −1 after 500 cycles at 1 A g −1 . Electrochemical analyses, including EIS, GITT, and pseudocapacitive behavior studies, revealed improved charge transfer kinetics, enhanced lithium-ion diffusion, and a dominant pseudocapacitive contribution in the Fe 2 O 3 @PAN composites. Post-cycling SEM confirmed the structural integrity of Fe 2 O 3 @PAN-9, attributed to optimal cyclization time that balances flexibility and conductivity of the PAN shell. This work not only offers an effective strategy for resource-efficient synthesis of Fe 2 O 3 -based anodes but also provides a scalable surface engineering route to enhance the electrochemical performance of transition metal oxide anodes for high-energy LIBs.