The Chemical Stability of Nasicon As a Solid Electrolyte for Seawater Batteries

Abstract

Seawater batteries have attracted significant attention for use as grid-scale energy storage systems (ESSs) due to the effective utilization of abundant resources of seawater as a catholyte. Sodium ions in seawater selectively transfer through a solid electrolyte to the anode for saving the chemical energy. For the selective transfer of sodium ions, NASICON (Na3Zr2Si2PO12) electrolytes are one of the suitable candidates for the solid electrolyte to prevent a short circuit between the catholyte and anode. However, NASICON powder is known to be dissolved in water because of the structural instability, leading to catastrophic failure of the system, while NASICON solid electrolytes are stable in seawater during the battery operation. In this regard, we have carefully compared the stability of NASICON powder and pellets in both DI water and seawater associated with different degradation mechanism. Figure shows the structural stability of NASICON pellets after the immersion tests in DI water and seawater indicative of the chemical stability of NASICON in seawater. In addition, the electrochemical performance shows higher stability of the seawater-immersed electrolyte than the DI water-immersed electrolyte. The corresponding analyses are carried out to confirm the effect of the investigation. Furthermore, we have employed polymer coating methods to enhance stability and performance as a seawater battery system. The coating layer enables to prevent direct contact with seawater, resulting in longer stability during operation without compromising ionic conductivity. These results reveal that NASICON solid electrolytes can be operated in seawater with high stability and performance. Figure. The chemical stability comparison of NASICON in seawater and DI water References Mauvy, F., Siebert, E., & Fabry, P. (1999). Reactivity of NASICON with water and interpretation of the detection limit of a NASICON based Na+ion selective electrode. Talanta , 48(2), 293–303. Fuentes, R. O., Figueiredo, F., Marques, F. M. B., & Franco, J. I. (2001). Reaction of NASICON with water, Solid State Ionics , 263, 309–314. Kim, Y., Kim, H., Park, S., Seo, I., & Kim, Y. (2016). Na ion- Conducting Ceramic as Solid Electrolyte for Rechargeable Seawater Batteries. Electrochimica Acta , 191, 1–7. Jung, J. Il, Kim, D., Kim, H., Jo, Y. N., Park, J. S., & Kim, Y. (2017). Progressive Assessment on the Decomposition Reaction of Na Superionic Conducting Ceramics. ACS Applied Materials & Interfaces , 9(1), 304–310. Figure 1

Designing a Novel Electrolyte Na3.2Hf2Si2.2P0.8O11.85F0.3 for All‐Solid‐State Na‐O2 Batteries

“…[13,14] NASICON electrolytes Na 1+x Zr 2 Si x P 3−x O 12 (0 ≤ x ≤ 3) had a high ionic conductivity, wide electrochemical window, and insensitive to water vapor, which helped them get a good application potential in sodium-air batteries. [15][16][17][18] In fact, NASICON electrolytes had been used in hybrid system sodium-air batteries. [19][20][21][22][23] However, the research of all-solid-state sodium-air batteries based on NASICON electrolyte was still insufficient and the catalytic mechanism in solid cathode was still unclear.Herein, we prepared an all-solid-state Na-O 2 battery based on elaborately designed NASICON electrolyte Na 3.2 Hf 2 Si 2.2 P 0.8 O 11.85 F 0.3 .…”

Prussian Blue‐Type Sodium‐ion Conducting Solid Electrolytes for All Solid‐State Batteries

“…[1,2] However, the limited availability of lithium (Li) resources in the Earth's crust, coupled with a sudden increase in the cost of Li precursors (e.g., Li 2 CO 3 and LiOH) and their uneven distribution across geological regions, poses significant challenges. [3][4][5][6][7] In addition, there are ongoing safety concerns regarding LIBs due to the potential risk of explosions and fire associated with the use of flammable organic liquid electrolytes. [8,9] These issues have precipitated the emergence of all-solid-state sodiumion batteries (ASNBs) as a promising alternative that can address both cost and safety concerns.…”