Abstract

In this study, we investigated the effects of ligand substitution in Prussian blue analog (PBA) cathode materials on the performance of aqueous sodium-ion batteries. NaCu[Fe(CN)6] (NaCuHCF) and ligand-modified PBAs, NaxCu[Fe(CN)5(C6H4N2)] (NaxCuCNPFe), and NaxCu[Fe(CN)5(CH3C6H4NH2)] (NaxCuTolFe) were tested in different electrolytes. The NaxCuCNPFe and NaxCuTolFe cathodes exhibited the best capacity retention of ∼50% after 2000 cycles in 1 M Na2SO4, which is much higher than that of the NaCuHCF cathode (0% capacity remained after 2000 cycles). To understand the charge–discharge mechanism of PBA cathodes, in situ synchrotron X-ray absorption spectroscopy and X-ray diffraction were performed. To demonstrate practical energy storage applications, PBAs were tested in full-cell configurations with an anode made of sodium titanium phosphate (NTP) coated with reduced graphene oxide and carbon (NTP@C@RGO). The NaxCuCNPFe//NTP@C@RGO and NaxCuTolFe//NTP@C@RGO full cells in 17 m NaClO4 aqueous electrolyte exhibited high power densities of up to 4338 W kg−1 (with an energy density of 18.11 Wh kg−1) and 4742 W kg−1 (with an energy density of 11.87 Wh kg−1), respectively. Our study demonstrates the potential of optimizing organic ligands in PBAs and electrolytes for the improvement of the cycling stability of high-power aqueous sodium-ion batteries.

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 call

Disclaimer: 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.