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.
展开▼
机译：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很大的应用前景。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，我们报告了一种钠超离子导体结构的电极，磷酸钒钒钛，它在0.1 C的速率下可提供147 mA h g -1 的高比容量，并在高速率下具有出色的容量保持率。对称的钠离子全电池显示出优异的倍率能力，在20 C的速率下比容量约为49 mA h g -1 ，在10,000个循环中具有超长寿命。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，鉴于其优异的倍率能力和长循环寿命，对称电池在电化学能量存储中的潜在应用。
展开▼
