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Scalable Preparation of Low-Cost Na2+xFe2(SO4)3−x(PO4)x Cathode with Superior Air Stability and High-Temperature Performance
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DOI:10.1021/acsaem.6c01002.png)
Abstract
En 中文
Alluaudite-type Na2Fe2(SO4)3 is a promising cathode material for low-cost sodium-ion batteries (SIBs). However, its practical application is severely hindered by the challenging pure-phase synthesis and poor air stability. Herein, PO43−-doped Na2Fe2(SO4)3 (Na2+xFe2(SO4)3−x(PO4)x, NFSP-x) was prepared via a scalable sand-milling/spray-drying strategy. Systematic characterizations confirm that homogeneous PO43− doping is realized without disrupting the lattice framework of Na2Fe2(SO4)3. The as-prepared NFSP-0.5 exhibits the highest phase purity and crystallinity among all samples. Electrochemical tests show that NFSP-0.5 delivers a reversible discharge capacity of 98.5 mA h g−1 at 0.1 C, excellent rate performance (87.5 mA h g−1 at 10 C), and long-term cycling stability (negligible capacity degradation over 1000 cycles at 10 C). Moreover, the NFSP-0.5 cathode achieves nearly no capacity decay over 50 cycles at 0.5 C in a sodium-ion full cell, demonstrating promising preliminary cycling stability for practical application. Meanwhile, NFSP-0.5 also shows superior air stability (no structural degradation after 7 days of air exposure) and outstanding high-temperature cycling performance (93.2% capacity retention after 800 cycles at 2 C and 60 °C). This work provides a scalable preparation strategy for high-performance polyanionic cathode materials for SIBs.
Keywords:
Na2+xFe2(SO4)3−x(PO4)x cathode
scalable preparation
air stability
high-temperature performance
sodium-ion batteries
Journal
IF:
5.5
Papers:
1.1W
Citations:
4.5W
