Nanoconfined Carbon-Coated Na3V2(PO4)3 Particles in Mesoporous Carbon Enabling Ultralong Cycle Life for Sodium-Ion Batteries
Nanoconfined Carbon-Coated Na3V2(PO4)3 Particles in Mesoporous Carbon Enabling Ultralong Cycle Life for Sodium-Ion Batteries
复制标题
介孔碳中的纳米碳包覆Na3V2(PO4)(3)颗粒使钠离子电池具有超长循环寿命
DOI：
10.1002/aenm.201402104
复制
发表时间：
2015-05-20
影响因子：
27.8
通讯作者：
Yu, Yan
中科院分区：
文献类型：
--
作者：
Jiang, Yu;Yang, Zhenzhong;Yu, Yan
Na3V2(PO4)(3)(记为NVP)被认为是一种很有前途的室温钠离子电池正极材料。然而，由于电子导电率低，NVP的倍率能力较差。本文报道了在高度有序的介孔碳CMK-3基质(NVP@C@CMK-3)中设计碳包裹的NVP纳米颗粒来实现高倍率性能的可行性。NVP@C@CMK-3是通过一种简单的纳米铸造技术制备的。与碳涂层负极和纯负极相比，该电极表现出更好的倍率性能和超长循环能力(2000次循环后5℃下的超长循环能力为78 mA h g(-1))。电化学性能的提高归功于双碳涂层的设计，该设计结合了多种优点：非常短的Na+/e(-)在NVP中的扩散长度，易于接触电解液，以及Na+通过碳向NVP纳米粒子的传输路径缩短，电子通过碳主体的3D互联通道的高导电性传输。具有双碳涂层的核壳纳米结构的优化设计允许传输的Na+离子和电子的快速动力学，从而实现高功率性能。
Na3V2(PO4)(3) (denoted as NVP) has been considered as a promising cathode material for room temperature sodium ion batteries. Nevertheless, NVP suffers from poor rate capability resulting from the low electronic conductivity. Here, the feasibility to approach high rate capability by designing carbon-coated NVP nanoparticles confined into highly ordered mesoporous carbon CMK-3 matrix (NVP@C@CMK-3) is reported. The NVP@C@CMK-3 is prepared by a simple nanocasting technique. The electrode exhibits superior rate capability and ultralong cyclability (78 mA h g(-1) at 5 C after 2000 cycles) compared to carbon-coated NVP and pure NVP cathode. The improved electrochemical performance is attributed to double carbon coating design that combines a variety of advantages: very short diffusion length of Na+/e(-) in NVP, easy access of electrolyte, and short transport path of Na+ through carbon toward the NVP nanoparticle, high conductivity transport of electrons through the 3D interconnected channels of carbon host. The optimum design of the core-shell nanostructures with double carbon coating permits fast kinetics for both transported Na+ ions and electrons, enabling high-power performance.