| Full text | |
| Author(s): |
Morais, William G.
;
Melo, Eduardo C.
;
Torresi, Roberto M.
Total Authors: 3
|
| Document type: | Journal article |
| Source: | MATERIALS ADVANCES; v. 5, n. 12, p. 10-pg., 2024-04-30. |
| Abstract | |
Sodium vanadium fluorophosphate (NVPF) has shown promising properties as a positive electrode in sodium-ion batteries mainly due to its high operating voltage; however, it has significant electronic and kinetic limitations that must be addressed. In this study, we investigated how a simple and straightforward mechanochemical treatment can be a valuable alternative to overcome these limitations. NVPF electrodes before and after (NVPF-bm) mechanochemical treatment were compared. For NVPF-bm, the contribution from the sodiation/desodiation of Na-1(+) increased from 23 to 40% as Na-2(+) decreased from 38 to 48% of the total produced capacity at similar to 0.5 C (70 mA g(-1)); additionally, the discharge capacities were 30% greater than those of NVPF at 0.8 C (100 mA g(-1)); nevertheless, after 150 cycles, NVPF-bm presented a coulombic efficiency of 96.2% and a capacity retention of 82.6%. The calculated diffusion coefficients for NVPF-bm were 22 x 10(-10) and 1.0 x 10(-10) cm(2) s(-1), compared to 6.5 x 10(-11) and 2.5 x 10(-11) cm(2) s(-1) for NVPF for the sodiation and desodiation processes, respectively. Furthermore, for the charge and discharge processes, NVPF-bm presented a charge transfer resistance three times smaller and diffusion lengths of 2.1 and 0.3 mu m, respectively, compared to 8.0 and 13 mu m, respectively, for NVPF. These results demonstrate the kinetic enhancements of the electrode as a direct consequence of the mechanochemical treatment. Therefore, this approach impacts not only the synthesis and morphology but also the inherent electrochemical storage capacity of the NVPF. (AU) | |
| FAPESP's process: | 18/23072-0 - Study of new active materials for application as positive and negative electrodes in sodium ion batterries |
| Grantee: | William Gomes de Morais |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |
| FAPESP's process: | 15/26308-7 - Optimization of the physicochemical properties of nano -structured materials for applications in molecular recognition, catalysis and energy conversion/storage |
| Grantee: | Roberto Manuel Torresi |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 21/00675-4 - Tying up materials for electrochemical energy storage and catalysis |
| Grantee: | Roberto Manuel Torresi |
| Support Opportunities: | Research Projects - Thematic Grants |