Wang Ye, Lim Yew Von, Huang Shaozhuan, Ding Meng, Kong Dezhi, Pei Yongyong, Xu Tingting, Shi Yumeng, Li Xinjian, Yang Hui Ying
Key Laboratory of Material Physics of Ministry of Education, School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450052, China and Pillar of Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, 487372, Singapore.
Pillar of Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, 487372, Singapore.
Nanoscale. 2020 Feb 20;12(7):4341-4351. doi: 10.1039/c9nr09278a.
Transition metal phosphides, such as iron phosphide (FeP), have been considered as promising anode candidates for high-performance sodium ion batteries (SIBs) owing to their high theoretical capacity. However, the development of FeP is limited by large volume change, low electrical conductivity and sluggish kinetics with sodium ions. Moreover, the sodium storage kinetics and dynamics behavior in FeP are still unclear. Herein, improved sodium storage ability of FeP is achieved by volume regulation and surface engineering via a rationally designed hierarchical porous FeP@C/rGO nanocomposite. This FeP@C/rGO nanocomposite exhibits excellent rate capability and long cycle life as the anode of SIBs. Specifically, the FeP@C/rGO nanocomposite delivers high specific capacities of 635.7 and 343.1 mA h g-1 at 20 and 2000 mA g-1, respectively, and stable cycling with 88.2% capacity retention after 1000 cycles. The kinetics and dynamics studies demonstrate that the superior performance is attributed to the rationally designed hierarchical porous FeP@C/rGO with a high capacitive contribution of 93.9% (at 2 mV s-1) and a small volume expansion of only 54.9% by in situ transmission electron microscopy (TEM) measurement. This work provides valuable insights into understanding the phase evolution of FeP during the sodiation/desodiation process for designing high-performance SIBs.
过渡金属磷化物，如磷化铁（FeP），由于其较高的理论容量，被认为是高性能钠离子电池（SIBs）有潜力的负极候选材料。然而，FeP的发展受到大体积变化、低电导率以及与钠离子缓慢动力学的限制。此外，FeP中的储钠动力学和动力学行为仍不清楚。在此，通过合理设计的分级多孔FeP@C/rGO纳米复合材料，通过体积调控和表面工程实现了FeP储钠能力的提升。这种FeP@C/rGO纳米复合材料作为SIBs的负极表现出优异的倍率性能和长循环寿命。具体而言，FeP@C/rGO纳米复合材料在20和2000 mA g-1下分别提供635.7和343.1 mA h g-1的高比容量，并在1000次循环后稳定循环，容量保持率为88.2%。动力学和动力学研究表明，优异的性能归因于合理设计的分级多孔FeP@C/rGO，其具有93.9%（在2 mV s-1）的高电容贡献，并且通过原位透射电子显微镜（TEM）测量，体积膨胀仅为54.9%。这项工作为理解FeP在嵌入/脱嵌过程中的相演变以设计高性能SIBs提供了有价值的见解。
