Enabling Sodium Compensation, Stable CEI Formation and Fast-Charging Using Thiocarbamate Additive in NVP Cathodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Sodium-ion batteries face instability issues from sodium loss and unstable cathode-electrolyte interfaces.
• Developing cost-effective cathode additives with low decomposition potentials is crucial for improving battery performance.

Purpose of the Study:

• To identify and evaluate a novel sodium compensating reagent for sodium-ion battery cathode materials.
• To investigate the efficacy of a thiocarbamate salt as a cathode additive for enhancing battery stability and performance.

Main Methods:

• A sodium salt of thiocarbamate was synthesized and characterized.
• The thiocarbamate additive was incorporated into Na3V2(PO4)3 cathode materials.
• Electrochemical performance, including discharge capacity, charging behavior, and cycling stability, was evaluated in full cells.

Main Results:

• The thiocarbamate salt decomposed into an amorphous N, S-rich cathode electrolyte interface (CEI) at low voltage.
• The additive effectively compensated for sodium losses during cycling.
• A 10 wt.% addition of thiocarbamate to Na3V2(PO4)3 significantly improved discharge capacity, charging behavior, and cathode stability.
• Energy density in full cells increased from 72.32 to 131.43 Wh kg-1.

Conclusions:

• Thiocarbamate salts are effective sodium compensating reagents for sodium-ion battery cathodes.
• The developed additive enhances cathode stability and energy density, showing promise for practical sodium-ion battery applications.