Zhang Jinyuan, Liu Haifeng, Tian Jiajun, Hu Endong, Gao Xiujuan, Hu Haitao, He Zhengyou, Wang Kangli, Jiang Kai, Tao Hongwei
Institute of smart city and intelligent transportation, Southwest Jiaotong University, Chengdu, 611756, P. R. China.
State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China.
Small. 2025 Aug 18:e07287. doi: 10.1002/smll.202507287.
Iron oxide (FeO) has attracted significant attention as a promising anode material for sodium-ion batteries (SIBs) due to its natural abundance, environmental benignity, and high theoretical capacity of 926 mA h g. Nevertheless, its practical application is limited by intrinsic drawbacks, including low electrical conductivity, sluggish Na⁺ diffusion kinetics, and severe volume variation during cycling, leading to rapid capacity fading and poor rate capability. To address these issues, a novel FeO/Fe@N-doped carbon (FeO/Fe@CN) nanostructure is rationally designed, which integrates FeO/Fe homogeneous heterojunctions with a uniform nitrogen-doped carbon shell. The built-in electric field at the Fe-FeO interface promotes charge redistribution and accelerates electron/ion transport, while the N-doped carbon shell enhances electrical conductivity and buffers mechanical stress during sodiation/desodiation processes. Benefiting from this synergistic structure, the FeO/Fe@CN anode delivers a high reversible capacity of 336.9 mA h g at 0.1 A g, excellent rate capability with 244.7 mA h g at 2 A g, and remarkable cycling stability, retaining 76.4% capacity after 500 cycles. Furthermore, a full cell assembled with a NaV(PO) cathode exhibits a high energy density of 112.67 Wh·kg at 51.42 W·kg and outstanding cycling performance. This study offers a versatile strategy to unlock the potential of FeO for high-performance SIB anodes through heterojunction and interfacial engineering.
氧化铁（FeO）作为一种有前景的钠离子电池（SIBs）负极材料，因其天然丰度、环境友好性以及926 mA h g的高理论容量而备受关注。然而，其实际应用受到固有缺点的限制，包括低电导率、缓慢的Na⁺扩散动力学以及循环过程中的严重体积变化，导致容量快速衰减和倍率性能不佳。为了解决这些问题，合理设计了一种新型的FeOO/Fe@N掺杂碳（FeO/Fe@CN）纳米结构，该结构将FeO/Fe均匀异质结与均匀的氮掺杂碳壳相结合。Fe-FeO界面处的内建电场促进电荷重新分布并加速电子/离子传输，而氮掺杂碳壳提高了电导率并在脱钠/嵌钠过程中缓冲机械应力。受益于这种协同结构，FeO/Fe@CN负极在0.1 A g下具有336.9 mA h g的高可逆容量，在2 A g下具有244.7 mA h g的优异倍率性能以及出色的循环稳定性，在500次循环后保持76.4%的容量。此外，与NaV(PO)正极组装的全电池在51.42 W·kg下表现出112.67 Wh·kg的高能量密度和出色的循环性能。这项研究提供了一种通用策略，通过异质结和界面工程释放FeO在高性能SIB负极方面的潜力。
