TY - JOUR
T1 - Transitioning from anhydrous Stanfieldite-type Na2Fe(SO4)2 Precursor to Alluaudite-type Na2+2δFe2-δ(SO4)3/C composite cathode
T2 - A pathway to cost-effective and all-climate sodium-ion batteries
AU - Yang, Wei
AU - Liu, Qi
AU - Yang, Qiang
AU - Lu, Shijie
AU - He, Wenxiu
AU - Li, Li
AU - Chen, Renjie
AU - Wu, Feng
N1 - Publisher Copyright:
© 2024 Elsevier B.V.
PY - 2025/1
Y1 - 2025/1
N2 - Low-cost and long-life cathode materials, such as the polyanionic iron-based Alluaudite-type Na2+2δFe2-δ(SO4)3, are crucial for future large-scale energy storage applications. This material is typically synthesized from the hydrated precursor Na2Fe(SO4)2·4H2O. However, the vapor released during the heating of crystal water can lead to reduced crystallinity, increased fraction of Na6Fe(SO4)4 impurities, and potential structural damage to Na2+2δFe2-δ(SO4)3. For the first time, we synthesized a stable Stanfieldite-type Na2Fe(SO4)2 material using a well-designed sol-gel method. This approach effectively mitigates the aforementioned risks by facilitating a unique transition from anhydrous Na2Fe(SO4)2 precursor to Na2+2δFe2-δ(SO4)3 cathode. The enhanced crystallinity, controllable impurity fraction, and reduced migration barriers of the pristine Na2+2δFe2-δ(SO4)3 cathode significantly improve electrochemical performance. Moreover, we constructed Na2+2δFe2-δ(SO4)3/C composite cathodes to optimize their high-rate capacity and cycling retention. At 25 °C, these composites exhibit remarkable high-rate capacity and maintain an impressive 92.2 % capacity retention after 1000 cycles at 10 C. In tests under extreme conditions at −25 °C, 0 °C, and 60 °C, they sustained over 90 % capacity retention after 100 cycles at 1 C or exceeded 95 % after 200 cycles at 2 C. Furthermore, the assembled Na2+2δFe2-δ(SO4)3/C//HC full cells demonstrate superior rate capacity and long-term cycling stability, indicating their promising potential for commercial applications.
AB - Low-cost and long-life cathode materials, such as the polyanionic iron-based Alluaudite-type Na2+2δFe2-δ(SO4)3, are crucial for future large-scale energy storage applications. This material is typically synthesized from the hydrated precursor Na2Fe(SO4)2·4H2O. However, the vapor released during the heating of crystal water can lead to reduced crystallinity, increased fraction of Na6Fe(SO4)4 impurities, and potential structural damage to Na2+2δFe2-δ(SO4)3. For the first time, we synthesized a stable Stanfieldite-type Na2Fe(SO4)2 material using a well-designed sol-gel method. This approach effectively mitigates the aforementioned risks by facilitating a unique transition from anhydrous Na2Fe(SO4)2 precursor to Na2+2δFe2-δ(SO4)3 cathode. The enhanced crystallinity, controllable impurity fraction, and reduced migration barriers of the pristine Na2+2δFe2-δ(SO4)3 cathode significantly improve electrochemical performance. Moreover, we constructed Na2+2δFe2-δ(SO4)3/C composite cathodes to optimize their high-rate capacity and cycling retention. At 25 °C, these composites exhibit remarkable high-rate capacity and maintain an impressive 92.2 % capacity retention after 1000 cycles at 10 C. In tests under extreme conditions at −25 °C, 0 °C, and 60 °C, they sustained over 90 % capacity retention after 100 cycles at 1 C or exceeded 95 % after 200 cycles at 2 C. Furthermore, the assembled Na2+2δFe2-δ(SO4)3/C//HC full cells demonstrate superior rate capacity and long-term cycling stability, indicating their promising potential for commercial applications.
KW - All-climate condition
KW - Alluaudite-type NaFe(SO)
KW - Iron-based polyanion
KW - Sodium-ion batteries
KW - Stanfieldite-type NaFe(SO)
UR - http://www.scopus.com/inward/record.url?scp=85211074746&partnerID=8YFLogxK
U2 - 10.1016/j.ensm.2024.103925
DO - 10.1016/j.ensm.2024.103925
M3 - Article
AN - SCOPUS:85211074746
SN - 2405-8297
VL - 74
JO - Energy Storage Materials
JF - Energy Storage Materials
M1 - 103925
ER -