A High-Voltage and Cycle Stable Aqueous Rechargeable Na-Ion Battery Based on Na₂Zn₃[Fe(CN)₆]₂–NaTi₂(PO₄)₃ Intercalation Chemistry

Abstract

Aqueous rechargeable Na-ion batteries (ARNBs) hold great promise for grid-scale electric energy storage because of their outstanding merits of low cost and resource abundance; however, their low energy density and poor cycling stability limit practical application. In this work, we reported a Prussian Blue (PB) analogue Na 2 Zn 3 [Fe-(CN) 6 ] 2 as a high-voltage aqueous cathode for ARNBs and achieved its stable cycling at a high operation potential of 1.13 V (vs SHE) by using of a highly concentrated NaClO 4 electrolyte. Raman spectroscopy, in situ XRD, and DFT calculations have been utilized to study the underlying mechanism of electrode performance as a function of electrolyte concentration. It was revealed that in the concentrated 17 m NaClO 4 electrolyte almost all the water molecules are coordinated with Na + ions, and the solvation energy of PB materials increases considerably with increasing salt concentrations, which broadens the electrochemical stability window of the electrolyte and greatly alleviates the dissolution of the materials. An aqueous rechargeable Na-ion battery was constructed by using a Na 2 Zn 3 [Fe(CN) 6 ] 2 cathode, a NaTi 2 (PO 4 ) 3 anode, and 17 m NaClO 4 electrolyte. This full cell demonstrates a high-voltage output of 1.6 V and an energy density of 55 Wh kg −1 (based on the total mass of the electrode-active materials), offering a viable alternative to commercial aqueous batteries for large-scale EES applications.

Advanced metal–organic frameworks for aqueous sodium-ion rechargeable batteries

“…In addition, the high concentration of NaClO 4 salt added with PEG inhibited the rapid dissolution or decomposition of the ZnHCF during charge/discharge cycling by suppressing the inherent water activity and expanding the stability window of the pristine aqueous electrolyte. Similar results were obtained for other Na 2 Zn 3 [Fe(CN) 6 ] 2 cathode materials cycled in a concentrated (17 mol kg À1 ) NaClO 4 aqueous electrolyte, where almost all the water molecules are coordinated with Na + ions, which could extend the electrochemical stability window of the aqueous electrolyte by mitigating the side reactions of H 2 and O 2 evolution [103]. In addition, an in situ XRD analysis confirmed the structural integrity of the ZnHCF during long-term Na + ion insertion/extraction cycles in the 17 mol kg À1 electrolyte, resulting in improved cycling performance (ca.…”

High‐Voltage and Super‐Stable Aqueous Sodium–Zinc Hybrid Ion Batteries Enabled by Double Solvation Structures in Concentrated Electrolyte

“…It is found that the rhombohedral ZnHCF is more stable than the cubic phase for long‐term galvanostatic charge/discharge cycling. [ 19 ] In our work, the rhombohedral–rhombohedral phase transition can maintain the structural integrity after repeated volumetric change during the insertion/extraction process and avoid the formation of cubic phase resulting in material dissolution, which is another critical factor to long‐term cyclability of cell in addition to concentrated aqueous electrolyte. As is known to all, the ZnHCF is prepared by the precipitation reaction to form a large network of FeCNZn units (metal‐organic framework) due to the coordination and chelating ability between Zn and N of FeCN.…”

“…As is known to all, the ZnHCF is prepared by the precipitation reaction to form a large network of FeCNZn units (metal‐organic framework) due to the coordination and chelating ability between Zn and N of FeCN. Therefore, the ZnHCF cathode in aqueous electrolyte encounters a partial dissolution, as shown below [ 19 ] …”

A Review of Battery Materials as CDI Electrodes for Desalination

“…NaTi 2 (PO4) 3 is one of the few appropriate aqueous sodium-ion battery anode materials that have been studied in the literature [124,125]. NTP is an environmentally friendly battery material with a high capacity of 133 mAh•g −1 and a suitable voltage plateau (about −0.6 V vs. SHE) just inside the voltage window of water [126,127]. [128] synthesized the NaTi 2 (PO4) 3 /rGO nanocomposite by a solvothermal reaction, which exhibited better desalination capacities and cycling abilities than pure NTP.…”

“…NaTi2(PO4)3 is one of the few appropriate aqueous sodium-ion battery anode materials that have been studied in the literature [124,125]. NTP is an environmentally friendly battery material with a high capacity of 133 mAh•g −1 and a suitable voltage plateau (about −0.6 V vs. SHE) just inside the voltage window of water [126,127].…”