Na2Fe(SO4)2: an anhydrous 3.6 V, low cost and good safety cathode for rechargeable sodium-ion battery

Wenli Pan, Wenhao Guan, Shuangyu Liu, Ben Bin Xu, Chu Liang, Hongge Pan, Mi Yan, Yingzhu Jiang

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)
9 Downloads (Pure)


Iron-based sulfate cathode materials are promising for rechargeable batteries due to their elevated operating voltages and earth-abundant elemental composition. However, the inherent unstable SO42- units in those sulfate materials result in their low-temperature decomposition (<450 °C) and lead to SO2 gas evolution, which would hinder sulfate electrodes from outputting high voltage in safety. Herein, a new alluaudite-type sulfate cathode Na2Fe(SO4)2 for sodium ion battery is reported, which displays a high operating voltage at ~3.6 V based on Fe2+/Fe3+ redox couple as well as superior thermal stability (~580 °C). In both air and inert ambient, its SO42-units demonstrates high thermal stability, assuring good safety for battery application. Furthermore, the Na2Fe(SO4)2 cathode material shows superior stability toward moisture for ease handling. The cathode exhibits a reversible capacity of 82 mAh g-1 at 0.1 C under nonoptimal carbon coating and maintains over 60% capacity retention at 2 C. The excellent sodium storage ability tested at 0 °C and 55 °C further demonstrates the advantages of Na2Fe(SO4)2 for future energy storage applications in a wide temperature range. The present exploration on Na2Fe(SO4)2 for sodium ion battery can pave the way for developing low cost sulfate cathodes combining high voltage and good safety.
Original languageEnglish
Number of pages9
JournalJournal of Materials Chemistry A
Early online date29 Apr 2019
Publication statusE-pub ahead of print - 29 Apr 2019


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