Revisiting the alluaudite NaMnFe2(PO4)3 sodium insertion material: Structural, diffusional and electrochemical insights
Revisiting the alluaudite NaMnFe2(PO4)3 sodium insertion material: Structural, diffusional and electrochemical insights
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DOI：
10.1016/j.electacta.2018.06.178
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发表时间：
2018-09
影响因子：
6.6
通讯作者：
Debasmita Dwibedi;P. W. Jaschin;Ritambhara Gond;P. Barpanda
中科院分区：
文献类型：
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作者：
Debasmita Dwibedi;P. W. Jaschin;Ritambhara Gond;P. Barpanda
在钠电池插入材料的范围中，NaMnFe 2（PO 4）3被报道为第一种透辉石骨架化合物，尽管具有差的电化学活性[Chem.Mater. 22（2010）5554]。本文报道了碳包覆钠锰铁2（PO4）3的自燃烧合成及其Na+扩散、离子电导率和电化学活性的协同效应实验。它记录了2.8 V的氧化还原活性，可逆容量为1060 mAh g− 1，具有良好的循环稳定性。BVSE计算显示了一个非常低的一维迁移势垒为0.31 eV的钠离子扩散。这是同步的低活化能势垒的0.162 eV来自交流阻抗谱。NaMnFe2（PO4）3钠锰矿阴极在室温下的电导率为0.5× 10− 6S cm− 1。在PO4基钠电池嵌件材料中，NaMnFe2（PO4）3钠锰矿具有很好的离子导电性，Na+迁移势垒很低。它可以导致在该铝钒土阴极中实现与LiFePO 4相当的上级可逆容量。
Among the gamut of sodium battery insertion materials, NaMnFe 2 (PO 4) 3 was reported as the first alluaudite framework compound albeit with poor electrochemical activity [Chem. Mater. 22 (2010) 5554]. We hereby report auto-combustion synthesis of carbon coated NaMnFe 2 (PO 4) 3 alluaudite and its Na+ diffusion, ionic conductivity and electrochemical activity synergizing experiments with bond valence site energy (BVSE) modeling. It registered a 2.8 V redox activity with a reversible capacity of∼ 60 mAh g− 1 with good cycling stability. BVSE calculations revealed an exceptionally low one-dimensional migration barrier of 0.31 eV for Na-ion diffusion. It was in sync with the low activation energy barrier of 0.162 eV derived from ac impedance spectroscopy. NaMnFe 2 (PO 4) 3 alluaudite cathode was found to have conductivity value of 0.5× 10− 6 S cm− 1 at room temperature. Among the PO 4-based sodium battery insertion materials, NaMnFe 2 (PO 4) 3 alluaudite shows excellent ionic conductivity with very low Na+ migration barrier. It can lead to the realization of superior reversible capacity in this alluaudite cathode comparable to LiFePO 4.