Abstract
This research work focuses on the synthesis and performance evaluation of NaFexCr1-X(SO4)2 (X = 0, 0.8 and 1.0) cathode materials in sodium ion batteries (SIBs). The novel materials having a primary particle size of around 100-200 nm were synthesized through a sol-gel process by reacting stoichiometric amounts of the precursor materials. The structural analysis confirms the formation of crystalline, phase pure materials that adopt a monoclinic crystal structure. Thermal analysis indicates the superior thermal stability of NaFe0.8Cr0.2(SO4)2 when compared to NaFe(SO4)2 and NaCr(SO4)2. Galvanostatic charge/discharge analysis indicates that the intercalation/de-intercalation of a sodium ion (Na+) into/from NaFe(SO4)2 ensues at about 3.2 V due to the Fe2+/Fe3+ active redox couple. Moreover, ex situ XRD analysis confirms that the insertion/de-insertion of sodium into/from the host structure during charging/discharging is accompanied by a reversible single-phase reaction rather than a biphasic reaction. A similar sodium intercalation/de-intercalation mechanism has been noticed in NaFe0.8Cr0.2(SO4)2which has not been reported earlier. The galvanostatic measurements and X-ray photoelectron spectroscopy (XPS) analysis confirm that the Cr2+/Cr3+ redox couple is inactive in NaFexCr1-X(SO4)2 (X = 0, 0.8) and thus does not contribute to capacity augmentation. However, suitable carbon coating may lead to activation of the Cr2+/Cr3+ redox couple in these inactive materials.
| Original language | English |
|---|---|
| Pages (from-to) | 32985-32991 |
| Number of pages | 7 |
| Journal | RSC Advances |
| Volume | 8 |
| Issue number | 57 |
| DOIs | |
| State | Published - 2018 |
| Externally published | Yes |
Funding
bDepartment of Chemical Engineering, College of Engineering, Qatar University, P. O. Box 2713, Doha, Qatar cQatar Environment and Energy Research Institute, Hamad Bin Khalifa University, Qatar Foundation, 5825, Doha, Qatar dDepartment of Chemistry & Earth Sciences, College of Arts and Science, Qatar University, P. O. Box 2713, Doha, Qatar eGas Processing Center (GPC), Qatar University, P. O. Box 2713, Doha, Qatar The authors acknowledge the nancial support from internal grant awarded by Center for Advanced Materials (CAM), Qatar University, Doha 2713, Qatar.
| Funders | Funder number |
|---|---|
| Hamad bin Khalifa University | |
| Qatar cQatar Environment and Energy Research Institute | |
| Center for Advanced Materials Processing, Clarkson University | |
| Qatar Foundation | |
| Buchtel College of Arts and Sciences | |
| Qatar University |
