Na₃ Zr₂ Si₂ PO₁₂ Solid Electrolyte Membrane for High-Performance Seawater Battery

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Seawater batteries (SWBs) offer low-cost, abundant energy storage but suffer from poor performance due to solid electrolyte (SE) interface issues, instability, and slow ion transport.
• Demonstration projects for SWBs are hindered by these electrochemical limitations, necessitating material improvements.

Purpose of the Study:

• To enhance the electrochemical performance of SWBs by addressing SE limitations.
• To investigate the effect of TiO2 doping on Nasicon-type Na3Zr2Si2PO12 (NZSP) SE for improved ionic conductivity and stability.

Main Methods:

• Constructed a surrogate SWB anode with a Na | SE | hard carbon configuration.
• Introduced tailored dopants, specifically TiO2, into the Nasicon-type Na3Zr2Si2PO12 (NZSP) SE membrane.
• Analyzed changes in SE pellet density, porous structure, surface chemistry, and bulk local structure.

Main Results:

• TiO2 doping resulted in a more densely packed NZSP pellet with a uniform porous structure.
• Observed improvements in ionic conductivity and critical current density of the TiO2-doped NZSP.
• Demonstrated stable cycling performance with reversible capacities attributed to enhanced Na storage mechanisms.

Conclusions:

• TiO2 doping significantly improves the structural and electrochemical properties of NZSP SE for SWB applications.
• Enhanced SE performance addresses key limitations in SWB technology, paving the way for more efficient long-duration energy storage.
• The study highlights a viable strategy for advancing SWB technology through targeted material modification.