Sodium Ion

Liquid Electrolytes To Enable Na-Metal/Na-Ion Batteries EXCELLENT CYCLING STABILITY OF SODIUM ANODE ENABLED BY A STABLE SOLID ELECTROLYTE INTERPHASE FORMED IN ETHER-BASED ELECTROLYTES

TUNING THE SOLVATION STRUCTURE WITH SALTS FOR STABLE SODIUM-METAL BATTERIES

Le et al. [1] demonstrate that 1M NaBF4 in G4 is able to achieve a coulombic efficiency of 99.9% with a Na anode for over 1000 cycles at a current density of 0.5 mA cm-2 with an areal capacity of 0.5 mAh cm-2. Against hard carbon anode, the electrolyte is able to reach 95% capacity retention over 300 cycles. XPS results reveal that the electrolyte generates a N-F and Na2-O rich CEI. Similarly on the anode side, XPS shows an SEI dominated by inorganic species.

He et al. [2] use NaNO3 salt as a diluent to tune the solvation structure and create a 1.1 M NaFSI-NaNO3-trimethyl phosphate electrolyte that stabilizes the Na metal anode - electrolyte interface. In Na || NFM cells, the electrolyte enabled a capacity retention of 80% over 500 cycles at a C/5 rate. Due to the presence of TMP, the electrolyte also demonstrates fire retarding abilities.

Le et al. show that G4 electrolytes containing 1M NaBF4 or 1M NaPF6 are promising candidates for practical Na-metal/Na-ion batteries.

Novel 1.1 M NaFSI-NaNO3-trimethyl phosphate electrolyte enables capacity retention of 80% over 500 cycles at a C/5 rate in Na || NFM cells.

Source: [1] Le, Phung ML, et al. "Excellent cycling stability of sodium anode enabled by a stable solid electrolyte interphase formed in ether‐based electrolytes." Advanced Functional Materials 30.25 (2020): 2001151.; [2]He, J., Bhargav, A., Su, L. et al. Tuning the solvation structure with salts for stable sodium-metal batteries. Nat Energy 9, 446–456 (2024). https://doi.org/10.1038/s41560-024-01469-y

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