Wenbin Li,Jianfeng Huang,Liangliang Feng,Liyun Cao,Shuwei He
Surface structure plays a decisive role in the surface capacity and electrochemical kinetics of rechargeable batteries. Tuning the surface structure of building blocks has been considered to be a new effective strategy to promote the electrochemical performance of 3D self-assembled nanoarchitectures. Herein, VS4 microspheres assembled from the nano-units with different crystallinities are synthesized via a facile template-free hydrothermal method. The results show that the electrochemical performance of VS4 microspheres as anode materials for sodium-ion batteries (SIBs) largely depends on their crystallinity, and a VS4 electrode with the lowest crystallinity delivers a high reversible capacity of 412 mA h g−1 at 0.2 A g−1 after 230 cycles and that of 345 and 293 mA h g−1 even at 1.0 and 2.0 A g−1, respectively. The insertion mechanism is revealed within the selected voltage window of 0.50–3.00 V. Further analysis suggests that decreasing the crystallinity of the nano-units can dramatically enhance the pseudocapacitive behavior of VS4 microspheres, which takes the main responsibility for the improvement of sodium storage properties. This work can provide a new insight for the exploration and design of high-performance anodes for SIBs.
Graphical Ordered channels, improved performance : Ordered and bridged nanoblocks-self-assembled VS 4 microspheres are prepared through a facile one-step hydrothermal method. The synergistic effect of (1 1 0)-oriented and bridged structures that collectively construct multidimensional Na + transfer channels in the VS 4 microspheres leads to an electrode that shows dramatically enhanced rate capability when used in Na-ion batteries. Developing 3 D self-assembled nanoarchitectures with well-defined crystal structures is an effective strategy to enhance the electrochemical performances of electrode materials. (1 1 0)-oriented and bridged-nanoblocks self-assembled VS 4 microspheres are controllably synthesized by a facile one-step hydrothermal method. The (1 1 0)-bridged structure sets up open pathways for Na + diffusion among nanoblocks, and the (1 1 0)-oriented structure provides unobstructed pathways for Na + diffusion in the nanoblocks, which collectively constructs multidimensional Na + transfer channels in the VS 4 microspheres, promoting the electrochemical kinetics. As an anode for Na-ion batteries (SIBs), this material exhibits pseudocapacitive Na + storage and excellent rate capability, delivering high capacities of 339 and 270 mAh g −1 at rates of 0.1 and 2.0 A g −1 , respectively, with a capacity retention of 79 % in the voltage window of 0.5–3.0 V. In particular, the reversible capacity reaches 575 mAh g −1 after 300 cycles even at 1.0 A g −1 in the voltage window of 0.05–3.0 V, outperforming those of the ever-reported VS 4 -based anode materials. This work presents an effective strategy to the exploration and design of high-performance anodes for SIBs.
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