Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University , No. 5 Xin Mofan Road, Nanjing 210009, China.
Chemical Engineering Department, Faculty of Engineering, Computing and Science, Swinburne University of Technology , Jalan Simpang Tiga, 93350 Kuching, Sarawak Malaysia.
ACS Appl Mater Interfaces. 2017 May 17;9(19):16280-16287. doi: 10.1021/acsami.7b03933. Epub 2017 May 5.
Sodium ion batteries (SIBs) are considered one of the most promising alternatives for large-scale energy storage due largely to the abundance and low cost of sodium. However, the lack of high-performance cathode materials at low cost represents a major obstacle toward broad commercialization of SIB technology. In this work, we report a green route strategy that allows cost-effective fabrication of carbon-coated NaFePOF cathode for SIBs. By using vitamin C as a green organic carbon source and environmentally friendly water-based polyacrylic latex as the binder, we have demonstrated that the NaFePOF phase in the as-derived NaFePOF/C electrode shows a high reversible capacity of 117 mAh g at a cycling rate of 0.1 C. More attractively, excellent rate capability is achieved while retaining outstanding cycling stability (∼85% capacity retention after 1000 charge-discharge cycles at a rate of 4 C). Further, in operando X-ray diffraction has been used to probe the evolution of phase structures during the charge-discharge process, confirming the structural robustness of the NaFePOF/C cathode (even when charged to 4.5 V). Accordingly, the poor initial Coulombic efficiency of some anode materials may be compensated by extracting more sodium ions from NaFePOF/C cathode at higher potentials (up to 4.5 V).
钠离子电池（SIBs）由于钠的丰富度和低成本而被认为是最有前途的大规模储能替代品之一。然而，缺乏低成本的高性能正极材料是 SIB 技术广泛商业化的主要障碍。在这项工作中，我们报告了一种绿色路线策略，该策略允许以经济有效的方式制造用于 SIB 的碳涂层 NaFePOF 正极。通过使用维生素 C 作为绿色有机碳源和环保的水性聚丙烯酸酯乳液作为粘结剂，我们已经证明，在衍生的 NaFePOF/C 电极中，NaFePOF 相具有 117 mAh g 的高可逆容量，在 0.1 C 的循环速率下。更具吸引力的是，在保持出色的循环稳定性（在 4 C 的倍率下经过 1000 次充放电循环后保持约 85%的容量）的同时，实现了优异的倍率性能。此外，还使用原位 X 射线衍射研究了在充放电过程中相结构的演变，证实了 NaFePOF/C 正极的结构稳定性（即使充电至 4.5 V 时也是如此）。因此，一些阳极材料初始库仑效率差的问题可以通过从 NaFePOF/C 正极在更高的电位（高达 4.5 V）下提取更多的钠离子来弥补。
