Fe2VO4 Hierarchical Porous Microparticles Prepared via a Facile Surface Solvation Treatment for High-Performance Lithium and Sodium Storage

Preventing the aggregation of nanosized electrode materials is a key point to fully utilize the advantage of the high capacity. In this work, a facile and low-cost surface solvation treatment is developed to synthesize Fe2VO4 hierarchical porous microparticles, which efficiently prevents the aggregation of the Fe2VO4 primary nanoparticles. The reaction between alcohol molecules and surface hydroxy groups is confirmed by density functional theory calculations and Fourier transform infrared spectroscopy. The electrochemical mechanism of Fe2VO4 as lithium-ion battery anode is characterized by in situ X-ray diffraction for the first time. This electrode material is capable of delivering a high reversible discharge capacity of 799 mA h g(-1) at 0.5 A g(-1) with a high initial coulombic efficiency of 79%, and the capacity retention is 78% after 500 cycles. Moreover, a remarkable reversible discharge capacity of 679 mA h g(-1) is achieved at 5 A g(-1). Furthermore, when tested as sodium-ion battery anode, a high reversible capacity of 382 mA h g(-1) can be delivered at the current density of 1 A g(-1), which still retains at 229 mA h g(-1) after 1000 cycles. The superior electrochemical performance makes it a potential anode material for high-rate and long-life lithium/sodium-ion batteries.