Sodium Rich Vanadium Oxy‐Fluorophosphate – Na<sub>3.2</sub>Ni<sub>0.2</sub>V<sub>1.8</sub>(P<sub>4</sub>)<sub>2</sub>F<sub>2</sub>O – as Advanced Cathode for Sodium Ion Batteries
<p dir="ltr">Conventional sodium‐based layered oxide cathodes are extremely air sensitive and possess poor electrochemical performance along with safety concerns when operating at high voltage. The polyanion phosphate, Na<sub>3</sub>V<sub>2</sub>(PO<sub>...
محفوظ في:
| المؤلف الرئيسي: | |
|---|---|
| مؤلفون آخرون: | , , , , , , , , , , |
| منشور في: |
2023
|
| الموضوعات: | |
| الوسوم: |
إضافة وسم
لا توجد وسوم, كن أول من يضع وسما على هذه التسجيلة!
|
| الملخص: | <p dir="ltr">Conventional sodium‐based layered oxide cathodes are extremely air sensitive and possess poor electrochemical performance along with safety concerns when operating at high voltage. The polyanion phosphate, Na<sub>3</sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> stands out as an excellent candidate due to its high nominal voltage, ambient air stability, and long cycle life. The caveat is that Na<sub>3</sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> can only exhibit reversible capacities in the range of 100 mAh g−1, 20% below its theoretical capacity. Here, the synthesis and characterizations are reported for the first time of the sodium‐rich vanadium oxyfluorophosphate, Na<sub>3</sub><sub>.2</sub>Ni<sub>0.2</sub>V<sub>1.8</sub>(PO<sub>4</sub>)<sub>2</sub>F<sub>2</sub>O, a tailored derivative compound of Na<sub>3</sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub>, with extensive electrochemical and structural analyses. Na<sub>3</sub><sub>.2</sub>Ni<sub>0.2</sub>V<sub>1.8</sub>(PO<sub>4</sub>)<sub>2</sub>F<sub>2</sub>O delivers an initial reversible capacity of 117 mAh g−1 between 2.5 and 4.5 V under the 1C rate at room temperature, with 85% capacity retention after 900 cycles. The cycling stability is further improved when the material is cycled at 50 °C within 2.8–4.3 V for 100 cycles. When paired with a presodiated hard carbon, Na<sub>3</sub><sub>.2</sub>Ni<sub>0.2</sub>V<sub>1.8</sub>(PO<sub>4</sub>)<sub>2</sub>F<sub>2</sub>O cycled with a capacity retention of 85% after 500 cycles. Cosubstitution of the transition metal and fluorine in Na<sub>3</sub><sub>.2</sub>Ni<sub>0.2</sub>V<sub>1.8</sub>(PO<sub>4</sub>)<sub>2</sub>F<sub>2</sub>O as well as the sodium‐rich structure are the major factors behind the improvement of specific capacity and cycling stability, which paves the way for this cathode in sodium‐ion batteries.</p><h2>Other Information</h2><p dir="ltr">Published in: Advanced Science<br>License: <a href="http://creativecommons.org/licenses/by/4.0/" target="_blank">http://creativecommons.org/licenses/by/4.0/</a><br>See article on publisher's website: <a href="https://dx.doi.org/10.1002/advs.202301091" target="_blank">https://dx.doi.org/10.1002/advs.202301091</a></p> |
|---|