Na0.97KFe(SO4)2: an iron-based sulfate cathode material with outstanding cyclability and power capability for Na-ion batteries,Journal of Materials Chemistry A

当前位置： X-MOL 学术 › J. Mater. Chem. A › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Na0.97KFe(SO4)2: an iron-based sulfate cathode material with outstanding cyclability and power capability for Na-ion batteries
Journal of Materials Chemistry A ( IF 10.7 ) Pub Date : 2018-08-09 , DOI: 10.1039/c8ta05854g
Wonseok Ko _{1,

2,

3,

4} , Teahoon Park _{4,

5,

6,

7,

8} , Hyunyoung Park _{1,

2,

3,

4} , Yongseok Lee _{1,

2,

3,

4} , Kang Eun Lee _{4,

5,

6,

7,

8} , Jongsoon Kim _{1,

2,

3,

4}

Affiliation

In this work, a novel cathode material for Na-ion batteries, Na_0.97KFe(SO₄)₂, was successfully prepared via slow evaporation and a low-temperature process, and its outstanding electrochemical performance was demonstrated. Based on the structural information of KFe(SO₄)₂ obtained from Rietveld refinement of X-ray diffraction data, the possible atomic sites for Na ions entering the structure were verified using bond-valence sum energy maps. Electrochemical measurements and X-ray absorption near-edge structure analyses revealed that ∼0.97 mol Na ions can be reversibly (de)intercalated into the structure via the Fe³⁺/Fe²⁺ redox reaction. The average redox potential of Na_0.97KFe(SO₄)₂ was shown to be ∼3.27 V (vs. Na⁺/Na), which is higher than that of other Fe-based phosphates owing to the inductive effect of (SO₄)²⁻. It was verified that the specific capacity of Na_0.97KFe(SO₄)₂ at C/10 was ∼85 mA h g⁻¹. At 10C (full charge/discharge in 12 min), ∼53% of its capacity measured at C/10 was retained. In addition, up to ∼99% of its initial capacity was retained over 200 cycles at 1C with a high coulombic efficiency of 99.3097%, which was attributed to the negligible volume change (∼1.8%) during charge/discharge.

中文翻译：

Na _0.97 KFe（SO ₄）₂：一种铁基硫酸盐正极材料，具有出色的循环能力和功率能力，可用于Na离子电池

在这项工作中，通过缓慢的蒸发和低温过程成功地制备了一种新型的Na离子电池正极材料Na _0.97 KFe（SO ₄）₂，并证明了其出色的电化学性能。基于Rietveld精制的X射线衍射数据获得的KFe（SO ₄）₂的结构信息，使用键价和能量图验证了Na离子进入结构的可能原子位。电化学测量和X射线吸收近边缘结构分析表明，约0.97 mol Na离子可通过Fe ³⁺ / Fe ²⁺可逆地（脱）嵌入结构中氧化还原反应。Na _0.97 KFe（SO ₄）₂的平均氧化还原电势为〜3.27 V（vs. Na ⁺ / Na），由于（SO ₄）的感应效应，其平均氧化还原电势高于其他基于Fe的磷酸盐。²⁻。证实Na _0.97 KFe（SO ₄）₂在C / 10时的比容量为〜85 mA hg ^-1。在10C（12分钟内充满/放电）时，保留了其在C / 10下测得的容量的〜53％。此外，在1C的200个循环中，高达〜99％的初始容量得以保留，库仑效率高达99.3097％，这归因于充电/放电期间的体积变化可忽略不计（〜1.8％）。

更新日期：2018-09-12

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南