Sun Pingping, Wang Yuanting, Wang Xiuzhen, Xu Qingyu, Fan Qi, Sun Yueming
School of Physics, Southeast University Nanjing 211189 China
National Laboratory of Solid State Microstructures, Nanjing University Nanjing 210093 China.
RSC Adv. 2018 Jun 4;8(36):20319-20326. doi: 10.1039/c8ra02843e. eCollection 2018 May 30.
NaV(PO) (NVP) is regarded as a promising cathode material for sustainable energy storage applications. Here we present an efficient method to synthesize off-stoichiometric Na V (PO)/C ( = 0-0.10) nanocomposites with excellent high-rate and long-life performance for sodium-ion batteries by high-energy ball milling. It is found that Na V (PO)/C nanocomposites with = 0.05 (NVP-0.05) exhibit the most excellent performance. When cycled at a rate of 1C in the range of 2.3-3.9 V, the initial discharge capacity of NVP-0.05 is 112.4 mA h g, which is about 96% of its theoretical value (117.6 mA h g). Even at 20C, it still delivers a discharge capacity of 92.3 mA h g (79% of the theoretical capacity). The specific capacity of NVP-0.05 is as high as 100.7 mA h g after 500 cycles at 5C, which maintains 95% of its initial value (106 mA h g). The significantly improved electrochemical performance of NVP-0.05 is attributed to the decrease of internal resistance and increase of the Na ion diffusion coefficient.
NaV(PO)（NVP）被认为是一种用于可持续储能应用的有前景的正极材料。在此，我们展示了一种通过高能球磨合成非化学计量比的Na V (PO)/C（ = 0 - 0.10）纳米复合材料的有效方法，该复合材料用于钠离子电池具有优异的高倍率和长寿命性能。发现 = 0.05的Na V (PO)/C纳米复合材料（NVP - 0.05）表现出最优异的性能。当在2.3 - 3.9 V范围内以1C的倍率循环时，NVP - 0.05的初始放电容量为112.4 mA h g，约为其理论值（117.6 mA h g）的96%。即使在20C时，它仍能提供92.3 mA h g的放电容量（理论容量的79%）。NVP - 0.05在5C下循环500次后的比容量高达100.7 mA h g，保持其初始值（106 mA h g）的95%。NVP - 0.05显著改善的电化学性能归因于内阻的降低和Na离子扩散系数的增加。
