Specific Electrolyte for Long-Cycling Sodium-Ion Battery (NFM111 + Hard Carbon), 200 g/bottle, CLCSIBSENFMHC

For an O3-type NaNi1/3Fe1/3Mn1/3O2 (NFM111) cathode paired with a Hard Carbon (HC) anode, achieving long cycle life (>1000–1500 cycles) requires an electrolyte formulated to address two distinct degradation pathways simultaneously: (1) Cathode Side (NFM111): Transition metal dissolution (Fe^{3+}/Mn^{3+} disproportionation and Jahn-Teller strain), surface lattice phase transitions (O3 to P3 to O3' above 3.9–4.0 V), and continuous electrolyte oxidation. (2) Anode Side (Hard Carbon): Solvent co-intercalation, continuous parasitic SEI growth at low potentials (<0.1 V vs. Na/Na+), and catalytic SEI breakdown triggered by migrated Fe/Mn/Ni ions.

The key additive packages & synergies are: (1) Tri-Additive System: FEC + PST + DTD: DTD preferentially adsorbs and coordinates with bare transition metal sites on the NFM111 surface, suppressing Fe/Mn stripping. Simultaneously, FEC builds a thin inorganic NaF inner SEI on the hard carbon, while PST polymerizes into an organic poly-sulfonate outer layer that buffers volume contraction/expansion during sodiation. (2) Dual-Salt Strategy: NaPF6 +NaFSI: Using pure NaFSI causes severe anodic pitting corrosion of the aluminum cathode current collector at potentials >3.6 V vs. Na/Na+. Blending 0.8 M NaPF6 + 0.3 M NaFSI allows PF6- to form a protective AlF3 surface layer on the Al foil, while FSI- dramatically improves low-temperature rate kinetics (-20°C) and yields a ductile, low-impedance SEI on hard carbon.

Notes: Please store the specific SIB electrolyte in the glovebox due to its sensitivity to humidity.

References: 

1. Y. Huang, et al. Multiple Functional Bonds Integrated Interphases for Long Cycle Sodium-Ion Batteries, Angew Chem. Int. Ed., 2024, 63, e202406277
2. M. D. L. Garayt, et al. Differential Voltage Analysis of Lead-Containing Sodium-Ion Full Cells, J. Electrochem. Soc., 2025, 172, 080513