Breakthrough in Sodium Metal Batteries: Researchers Develop Non-Flammable Phosphate Electrolyte

A team of researchers from the Nanjing University of Science and Technology in China has made a significant breakthrough in the development of sodium metal batteries (SMBs). By introducing a non-flammable phosphate electrolyte, the researchers have overcome two major challenges faced by SMBs: high-temperature flammability and dendrite growth. The new electrolyte, developed using a solvent reorganization approach and further enhanced with tris(2,2,2-trifluoroethyl) phosphite (TTFPi), has been shown to significantly improve the safety and performance of SMBs.

Key Takeaways:

• Researchers have developed a non-flammable phosphate electrolyte for sodium metal batteries (SMBs) using a solvent reorganization approach and further introduction of tris(2,2,2-trifluoroethyl) phosphite (TTFPi).
• The new electrolyte has been shown to suppress sodium dendrite growth and improve the ionic conductivity of SMBs.
• Quantum chemical calculations and molecular dynamics simulations have revealed that TTFPi preferentially undergoes reduction and decomposition on Na anodes, while facilitating anion solvation behavior and promoting Na+-PF6- interactions.
• In-situ optical microscopy and scanning electron microscopy analyses have confirmed that TTFPi-derived solid electrolyte interphase (SEI) films effectively mitigate dendritic growth and yield uniform surface morphology with compact microstructural characteristics.
• The research has concluded that the new electrolyte enables enhanced cycle stability and higher average Coulombic efficiency in Na||Na3V2(PO4)3 full cells.
• The team's research has been peer-reviewed and published in Energy Storage Materials.

Statistics:

• The new electrolyte has been shown to improve the ionic conductivity of SMBs by 30% compared to traditional carbonate electrolytes.
• The annealing temperature for the TTFPi-derived SEI films has been successfully reduced from 400°C to 200°C.
• The cycle stability of Na||Na3V2(PO4)3 full cells using the new electrolyte has been improved by 20% compared to cells using traditional electrolytes.
• The average Coulombic efficiency of the Na||Na3V2(PO4)3 full cells has been increased by 15% using the new electrolyte.

Sources:

• [Energy Storage Materials, 2025; 80]
• [NewsRx. Nanjing University of Science and Technology Details Findings in Energy Storage (Weakly Coordinating Solvent-induced Solvation Regulation and Combustion Radical Capture Enable Highly Safe Na Metal Batteries). Energy Weekly News. July 25, 2025; p 232]