Na-ion batteries have attracted great attention because of their prospective sustainability and low cost, and are regarded as one of the most promising energy storage devices for post- Li-ion battery generation. However, the intrinsic limitations of Na-ion batteries are constraining its application, such as lower voltage and poor diffusion ability. Here, we successfully synthesized hierarchical zigzag Na1.25V3O8 nanowires via the facile topotactic intercalation method. The as-synthesized materials exhibit outstanding performance as Na- ion battery cathode: it delivers a capacity of 172.5 mA h g-1 at 100mA g-1, shows excellent cyclability with a capacity fading of only 0.0138% per cycle at 1 A g-1 for 1000 cycles, and at 2 A g-1, the capacity still reaches 79.1 mAh g-1. We propose that the significantly enhanced performance is due to the synergistic effect of the unique morphology and optimized crystal structure stability. The hierarchical structure provides more surface area of the nanowires, which facilitates electrochemical reactions and ensures efficient penetration of the electrolyte into the active materials, endowing the hierarchical nanowires with a reduced Na ion diffusion length, thus resulting in improved electrochemical kinetics. Besides, the topotactic intercalation method can improve the crystal structure robustness effectively without damaging the morphology, which improves the structure integrity and robustness.
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机译：由于其前瞻性可持续性和低成本，Na离子电池引起了极大的关注，并且被视为锂电站电池的最有前途的能量存储装置之一。然而，Na离子电池的内在限制是限制其应用，例如较低的电压和差的扩散能力。在这里，我们通过便于拓扑插相方法成功地合成了等级Zigzag Na1.25V3O8纳米线。作为Na离子电池阴极的优异性能表现出优异的性能：它在100mA G-1中提供172.5 mA H G-1的容量，显示出优异的可控制性，其容量衰落仅为每循环的0.0138％，1 a g- 1持续1000个循环，在2 A G-1，容量仍然达到79.1mAhg-1。我们建议显着增强的性能是由于独特形态和优化的晶体结构稳定性的协同效应。等级结构提供了纳米线的更多表面积，这有利于电化学反应，并确保电解质的有效渗透到活性材料中，赋予具有降低的Na离子扩散长度的分级纳米线，从而导致改善的电化学动力学。此外，拓扑嵌入方法可以有效地改善晶体结构的鲁棒性，而不会损坏形态，这提高了结构完整性和鲁棒性。
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