Effects of the pH of Solution on the Structure and Electrochemical Performance of Na3V2O2 (PO4)2F Cathode Material for Sodium-Ion Battery Synthesized
via Hydrothermal Method(PDF)
MATERIALS CHINA[ISSN:1674-3962/CN:61-1473/TG]
Issue:
2025年09
Page:
862-867
Research Field:
Publishing date:
Info
Title:
Effects of the pH of Solution on the Structure and Electrochemical Performance of Na3V2O2 (PO4)2F Cathode Material for Sodium-Ion Battery Synthesized
via Hydrothermal Method
1 National and local joint engineering research center of lithium-ion batteries and materials preparation technology，Kunming 650093，China
2 State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization，Panzhihua Iron & Steel Group Research Institute Co.Ltd.Panzhihua 617000，China
Adopting V2O5, NH4H2PO4, Na2CO3 and NaF as the raw materials, oxalic acid dihydrate as reducing agents, hydrothermal insulation at 150 ℃ as synthetic conditions, Na3V2O2(PO4)2F(NVPOF), has been successfully synthesized.Meanwhile, the effect of pH values of the solution on materials-sodium-storage structure and electrochemical performance is systematically studied. To be specific, the pH value generates influences on the lattice structure, morphology and particle size distribution of NVPOF. As the increasing of the pH values (1.8~4.0) of the solution, the particle sizes are increased with the morphology morphing from flocculent to cube. When the pH value of the solution reaches at 2.0, the synthesized material (NVPOF-pH2.0) possesses excellent crystallinity, minimum cell parameter value and cell volume, tiny and uniform particle size, which is conducive to the transportation and storage of Na+ during the charge/discharge process. As is shown from the results of electrochemical tests, compared with NVPOF synthesized from the other solutions with different pH values, NVPOF-pH2.0 shows the optimal cycling performances and rate performances. Particularly, even after 500 cycling periods under 1C, NVPOF-pH2.0 exhibits the discharging specific capacity at 72.7 mAh·g-1 and retention rate at 66.0%.