High-Entropy Inorganic Solid Electrolyte Interphase Enables Thermally Safe Sodium-Ion Battery with Deep Sodium...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Widespread adoption of sodium-ion batteries is hindered by thermal safety concerns.
• Conventional organic interfaces lack thermal stability, failing to protect sodiated hard carbon.
• Reactive sodium clusters formed during storage pose significant safety risks.

Purpose of the Study:

• To develop a thermally stable interface for sodium-ion batteries.
• To enhance sodium storage capacity and improve battery safety.
• To investigate the impact of a high-entropy solid electrolyte interphase on hard carbon.

Main Methods:

• Construction of a dual-functional high-entropy solid electrolyte interphase on hard carbon.
• Characterization of the interface's structure and ion transport properties.
• Electrochemical testing of sodium-ion coin cells and cylindrical cells, including cycling stability and energy density measurements.
• Thermal safety evaluation of pouch cells under abuse conditions.

Main Results:

• The high-entropy inorganic interface facilitates deep sodium-ion storage via pore-filling pathways, increasing capacity.
• NaNi_1/3Fe_1/3Mn_1/3O₂/hard carbon cells show 80% capacity retention after 800 cycles.
• A 3.7 Ah 26700 cylindrical cell achieved an energy density of 146.2 Wh kg^-1.
• Thermal runaway onset temperature increased from 52.4 to 161.9 °C, and temperature rise rate decreased significantly.

Conclusions:

• The developed high-entropy inorganic interface effectively enhances sodium storage and significantly improves the thermal safety of sodium-ion batteries.
• This approach offers new strategies for modulating sodium storage mechanisms and mitigating safety risks in next-generation energy storage.