Cao JiaLi,Ni Liang,Qin CanCan,Tang YueFeng,Chen YanFeng
Hierarchical Na 2 FeP 2 O 7 spheres with nanoparticles were successfully fabricated by a facile spray drying method. A relatively low drying temperature was introduced in order to form a carbon layer on the surface. As a cathode material for sodium-ion batteries, it delivered a reversible capacity of 84.4 mAh g −1 at 0.1 C and showed excellent cycling and rate performance (64.7 mAh g −1 at 5 C). Furthermore, a full sodium battery was fabricated using SP-Na 2 FeP 2 O 7 as the cathode and hard carbon as the anode, suffering almost no capacity loss after 400 cycles at 1 C. Due to its superior electrochemical property and the low materials cost, Na 2 FeP 2 O 7 is becoming a promising cathode material for large-scale energy storage systems.
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 °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.
危险品化学品经营许可证（带存储）