Comparative Investigation of Na2FeP2O7 Sodium Insertion Material Synthesized by Using Different Sodium Sources
Comparative Investigation of Na2FeP2O7 Sodium Insertion Material Synthesized by Using Different Sodium Sources
复制标题
不同钠源合成的Na2FeP2O7钠嵌入材料的对比研究
DOI：
10.1021/acssuschemeng.7b04516
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发表时间：
2018-04-01
影响因子：
8.4
通讯作者：
Zhang, Jia-feng
中科院分区：
文献类型：
--
作者：
Zheng, Jun-chao;Yang, Bi-yuan;Zhang, Jia-feng
以Na 2CO 3、NaH 2 PO 4和NaOH为钠源，采用固相法合成了Na 2FeP 2 O 7粉体，并对其固相反应机理和电化学性能进行了研究。结果表明，NaH 2 PO 4有利于晶体表面生长，使晶体表面间距变宽，有利于钠离子的嵌入和脱嵌。其中以NaH 2 PO 4为原料在600 ℃合成的Na 2FeP 2 O 7具有最好的电化学性能，在C/10、C/5、C/2、1C、2C和5C循环倍率下的首次放电容量分别为82.8、79.4、77.9、75.3、68.8和47.8 mAh g（-1）。在不同的循环速率下，电池的可逆容量为81.0mAh g（-1）（C/10），约为理论容量的83.5%。在C/2下循环140次后，容量保持率约为93.3%。结果表明，选择合适的钠源对合成性能良好的Na 2FeP 2 O 7至关重要。
Na2FeP2O7 powders were synthesized by a solid-state method by using different sodium sources (Na2CO3, NaH2PO4, and NaOH), and their solid-state reaction mechanism and the electrochemical properties of the synthesized Na2FeP2O7 were studied in detail. The results indicate that NaH2PO4 is conducive to the growth of the crystal surface with a wider spacing, which contributes to sodium-ion intercalation and deintercalation. Na2FeP2O7 synthesized at 600 degrees C by using NaH2PO4 exhibits the best electrochemical performance among them, showing an initial discharge capacity of 82.8, 79.4, 77.9, 75.3, 68.8, and 47.8 mAh g(-1) under the cycle rate of C/10, C/5, C/2, 1C, 2C, and 5C, respectively. Moreover, a reversible capacity of 81.0 mAh g(-1) at C/10, about 83.5% of the theoretical capacity, can be achieved after different cycle rates. The capacity retention is about 93.3% after 140 cycles under C/2. The results indicate that it is very important to choose the right sodium sources to synthesize Na2FeP2O7 with a good performance.