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>Moving to Aqueous Binder: A Valid Approach to Achieving High‐Rate Capability and Long‐Term Durability for Sodium‐Ion Battery
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Moving to Aqueous Binder: A Valid Approach to Achieving High‐Rate Capability and Long‐Term Durability for Sodium‐Ion Battery
Polyanionic Na3V2(PO4)2F3 with a NASICON‐type structure is heralded as a promising cathode material for sodium‐ion batteries due to its fast ionic conduction, high working voltage, and favorable structural stability. However, a number of challenging issues remain regarding its rate capability and cycle life, which must be addressed to enable greater application compatibility. Here, a facile and effective approach that can be used to overcome these disadvantages by introducing an aqueous carboxymethyl cellulose (CMC) binder is reported. The resulting conductive network serves to accelerate the diffusion of Na+ ions across the interface as well as in the bulk. The strong binding force of the CMC and stable solid permeable interface protect the electrode from degradation, leading to an excellent capacity of 75 mA h g−1 at an ultrahigh rate of 70 C (1 C = 128 mA g−1) and a long lifespan of 3500 cycles at 30 C while sustaining 79% of the initial capacity value. A full cell based on this electrode material delivers an impressive energy density as high as 216 W h kg−1, indicating the potential for application of this straightforward and cost‐effective route for the future development of advanced battery technologies.
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机译:具有NASICON型结构的聚阴离子Na3V2(PO4)2F3因其快速的离子传导,高工作电压和良好的结构稳定性而被认为是钠离子电池的有希望的正极材料。但是,关于其速率能力和循环寿命,仍然存在许多具有挑战性的问题,必须解决这些问题才能实现更大的应用程序兼容性。在此,报道了一种可通过引入水性羧甲基纤维素(CMC)粘合剂来克服这些缺点的简便有效的方法。所得的导电网络用于加速Na + sup>离子在整个界面以及整个体内的扩散。 CMC的强大结合力和稳定的固体可渗透界面可保护电极免于降解,从而在70 C(1 C = 128 mA g)的超高速率下产生75 mA hg -1 sup>的出色容量 -1 sup>),在30 C下具有3500个循环的长寿命,同时维持初始容量值的79%。基于这种电极材料的完整电池可提供高达216 W h kg -1 sup>的出色能量密度,这表明这种简单且经济高效的路线可能会应用于未来高级电池的开发技术。
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