Enhanced electrode kinetics and electrochemical properties of low-cost NaFe2PO4(SO4)2 via Ca2+doping as cathode material for sodium-ion batteries

• 作者: Shao-Fang Li Zhen-Yi Gu Jin-Zhi Guo Xian-Kun Hou Xu Yang Bo Zhao Xing-Long Wu
• 来源期刊: 材料科学技术（英文版）
• 年，卷（期）: 2021,（19）
• 页码范围: 176-182
• 页数: 7页
• 语种: 英文

摘要

In recent years,sodium-ion batteries(SIBs)have been considered as one of the most promising alterna-tives to lithium-ion batteries(LIBs).Here,a new Na-super-ionic conductor(NASICON)cathode material NaFe2PO4(SO4)2 is successfully prepared through solid state method for SIBs.While the poor electronic conductivity of iron-based materials results in its poor rate and cycle performance.Then the electro-chemical is effectively promoting via Ca2+doping.Na0.84Ca0.08Fe2PO4(SO4)2 have achieved considerable electrochemical properties.The first discharge specific capacity is 121.6mAhg-1 at 25mAg-1 with the voltage platform(～3.1 V)corresponding to Fe2+/3+.After 100 cycles,the capacity retention is 55.1％.The excellent electrochemical performance is caused by some Na+is substituted by Ca2+and leading to the fast sodium kinetics,which is well proved by the powder X-ray diffraction pattern and well corresponding to the galvanostatic intermittent titration technique and cyclic voltammetry testing result(the diffusivity values are around at 10-12 cm2 s-1).