柔性三维网络钒酸铁纳米片阵列/碳布作为镁离子电池高性能正极材料

Flexible three-dimensional-networked iron vanadate nanosheet arrays/carbon cloths as high-performance cathodes for magnesium ion batteries

镁离子电池由于具有高安全性、低成本等优点,近年来受到了广泛的关注.然而,镁离子缓慢的扩散动力学使其难以找到合适的具有良好电化学性能的正极材料.在此,我们设计并合成了一种新颖的柔性三维网络钒酸铁纳米片阵列/碳布(3D FeVO/CC)作为镁离子电池的无粘结剂正极材料.与原始钒酸铁纳米片(FeVO)相比,结构改善的3D无粘结剂电极能够实现全面的电化学性能优化,包括高比容量(270 mA h g^(-1))和更长的循环寿命(超过5000次循环).这种可实现的高能量密度来源于电子和离子动力学的协同优化,而循环稳定性得益于稳固的分级结构.本文采用原位X射线衍射和拉曼技术对镁离子储存过程中FeVO单相反应机理进行了研究.此外,还组装了柔性镁离子全电池(3D FeVO/CC|MgNaTi(3)O_(7)),并展示出一定的应用潜力.本工作证明了3D FeVO/CC是一种有潜力的正极材料,可以满足高性能镁离子电池的要求,也为提高镁离子电池正极材料的电化学性能开辟了一条新的途径.

Owing to their safety and low cost,magnesium ion batteries(MIBs)have attracted much attention in recent years.However,the sluggish diffusion dynamics of magnesium ions hampers the search for appropriate cathode materials with excellent electrochemical performance.Herein,we design and synthesize a novel flexible three-dimensional-networked composite of iron vanadate nanosheet arrays/carbon cloths(3 D FeVO/CC)as a binder-free cathode for MIBs.Relative to bare FeVO nanosheets,the 3 D binder-free electrode with designed architecture enables a full range of electrochemical potential,including a high specific capacity of270 mA h g^(-1) and an increased life span(over 5000 cycles).Such achievable high-density energy originates from the synergistic optimization of electron and ion kinetics,while the durability benefits from the robust structure that prevents degradation in cycling.The single-phase reaction mechanism of FeVO in the magnesium ion storage process is also explored by in-situ X-ray diffraction and Raman technologies.Moreover,a flexible MIB pouch cell(3 D FeVO/CCIMgNaTi_(3)O_(7)) is assembled and exhibits practical application potential.This work verifies that 3 D FeVO/CC is a potential candidate cathode material that can satisfy the requirements of highperformance MIBs.It also opens a new avenue to improve the electrochemical performance of cathode materials for MIBs.