Abstract
Na2Fe0.6Mn0.4PO4F/C composite materials are synthesized with various carbon sources via a simple spray-drying method in this study, and the effect of carbon sources on structure, morphology, and electrochemical properties of Na2Fe0.6Mn0.4PO4F/C materials are investigated in detail. XRD and SEM results indicate that the reduction ability of carbon sources has a key impact on the structure and morphology of Na2Fe0.6Mn0.4PO4F/C composite materials. Among these Na2Fe0.6Mn0.4PO4F/C materials, the sample prepared with ascorbic acid presents a uniform hollow spherical architecture. Electrochemical analysis demonstrates that the Na2Fe0.6Mn0.4PO4F/C sample prepared with ascorbic acid has optimal electrochemical performance. The sample shows high discharge capacities of 95.1 and 48.1 mAh g−1 at 0.05C and 1C rates, respectively, and it exhibits an improved cycle stability (91.7% retention after 100 cycles at 0.5C), which are superior to Na2Fe0.6Mn0.4PO4F/C materials prepared with other carbon sources. This study demonstrates that the reduction ability of carbon sources significantly influences the electrochemical properties of fluorophosphate/C composite materials. This work also provides a promising strategy to obtain high performance cathode materials for sodium-ion batteries.
Highlights
In recent years, the demand for lithium-ion batteries (LIBs) has increased sharply due to the rapid development of large-scale energy storage and electric vehicles (Wu et al, 2016; Li et al, 2020; Nie et al, 2020a; Shen et al, 2020; Sui et al, 2020a)
It can be seen that the synthesized Na2Fe0.6Mn0.4PO4F/C samples with different carbon sources show different peak intensities and widths: the sample prepared with glucose exhibits the highest peak intensity, citric acid takes the second place, and the sample prepared with oxalic acid presents the lowest peak intensity
The results show that the reduction ability of carbon sources plays a key role in the morphology of Na2Fe0.6Mn0.4PO4F/C materials, and the material prepared with ascorbic acid presents the most perfect hollow spherical shape
Summary
The demand for lithium-ion batteries (LIBs) has increased sharply due to the rapid development of large-scale energy storage and electric vehicles (Wu et al, 2016; Li et al, 2020; Nie et al, 2020a; Shen et al, 2020; Sui et al, 2020a). The operating voltage and energy density of sodium-ion batteries (SIBs) are generally lower than those of LIBs, as the standard electrode potential of Na/Na+ (−2.71 V) is higher than that of Li/Li+ (−3.04 V) (Zhu et al, 2013; Wu et al, 2019; Nie et al, 2020b). It is very important to develop new cathode materials with high voltages to improve the energy density of SIBs (Wu et al, 2018a; Zheng et al, 2018)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
