In recent years, oxygen-defect (vacancies) and nanostructured-based materials have been fabricated and applied as electrode materials for lithium-ion batteries (LIBs). However, the individual role of oxygen defects and nanostructuring on the improvement of Li-storage performance is still not clear. In addition, the technique which generates the control amount of oxygen-defects as well as maintains the nanostructured morphology of the electrode materials is highly desirable. Hence, in this work, we have attempted to create the oxygen defects in Ca₂Fe₂O₅ (C2FONF) nanofibers via electrospinning technique and subsequent heat-treatment on as-spun nanofibers such as 700 °C (C2FONF-700), 800 °C (C2FONF-800), and 900 °C (C2FONF-900). All the as-prepared samples are characterized by XRD, FE-SEM, BET, XPS, and I-V characteristics. From the quantification of oxygen defect, it is observed that C2FONF-900 sample consists of the highest number of oxygen defects. As an LIB anode, C2FONF-900 exhibits superior reversible capacity (530 (±10) mAh g⁻¹ at 50 mAg⁻¹ up to 100 cycles), cyclability (370 (±10) mAh g⁻¹ at 1C: 500 mAg⁻¹ up to 100 cycles). Further, the rate capability of C2FONF-900 is found better than the C2FONF-700 and C2FONF-800. Furthermore, the study of capacitive/diffusion-controlled process showed the higher contribution of capacitive capacity in the C2FONF-900 electrodes, which is responsible for their better rate capability. In this study, we have shown that the Li-storage properties of iron-based oxides can be easily improved by tuning their concentration of oxygen defects while maintaining similar fibric nanostructure.

近年来，氧缺陷（空位）和基于纳米结构的材料已被制造出来并用作锂离子电池（LIB）的电极材料。然而，氧缺陷和纳米结构对改善锂存储性能的个别作用仍不清楚。另外，非常需要产生控制氧缺陷量并保持电极材料的纳米结构形态的技术。因此，在这项工作中，我们试图在Ca ₂ Fe ₂ O _5中产生氧缺陷。（C2FONF）纳米纤维通过静电纺丝技术以及随后对初生纳米纤维的热处理，例如700°C（C2FONF-700），800°C（C2FONF-800）和900°C（C2FONF-900）。所有制备的样品均具有XRD，FE-SEM，BET，XPS和IV特性。从氧缺陷的定量可以看出，C2FONF-900样品包含最多的氧缺陷。作为LIB阳极，C2FONF-900表现出优良的可逆容量（530（±10）毫安克^-1在50 MAG ^-1高达100个循环），可循环性（370（±10）毫安克^-1在1C：500 MAG ^{- 1个}最多100个周期）。此外，发现C2FONF-900的速率能力比C2FONF-700和C2FONF-800更好。此外，对电容/扩散控制过程的研究表明，C2FONF-900电极对电容容量的贡献更大，这是其更好的倍率能力的原因。在这项研究中，我们已经表明，通过调整氧缺陷的浓度同时保持相似的纤维纳米结构，可以轻松地改善铁基氧化物的锂存储性能。