Sodium-ion batteries operating at ambient temperature hold great promise for use in grid energy storage owing to their significant cost advantages. However, challenges remain in the development of suitable electrode materials to enable long lifespan and high rate capability. Here we report a sodium super-ionic conductor structured electrode, sodium vanadium titanium phosphate, which delivers a high specific capacity of 147 mA h g^-1 at a rate of 0.1 C and excellent capacity retentions at high rates. A symmetric sodium-ion full cell demonstrates a superior rate capability with a specific capacity of about 49 mA h g^-1 at 20 C rate and ultralong lifetime over 10,000 cycles. Furthermore, in situ synchrotron diffraction and X-ray absorption spectroscopy measurement are carried out to unravel the underlying sodium storage mechanism and charge compensation behaviour. Our results suggest the potential application of symmetric batteries for electrochemical energy storage given the superior rate capability and long cycle life.

中文翻译：

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钠钒钛磷酸盐磷酸酯电极，用于高功率，长寿命的对称钠离子电池。

由于钠离子电池具有显着的成本优势，因此在环境温度下运行的钠离子电池具有广阔的前景。然而，在开发合适的电极材料以实现长寿命和高倍率能力方面仍然存在挑战。在这里，我们报道了一种钠超离子导体结构电极，即磷酸钒钒钛，它能以0.1 C的速率提供147 mA h g ^-1的高比容量，并能以高速率保持出色的容量。对称的钠离子全电池展示出卓越的速率能力，比容量约为49 mA h g ^-1在20 C的速率下具有10,000个循环的超长寿命。此外，还进行了原位同步加速器衍射和X射线吸收光谱测量，以揭示潜在的钠存储机理和电荷补偿行为。我们的结果表明，鉴于其优异的倍率性能和长循环寿命，对称电池在电化学能量存储中的潜在应用。