Ion-Dipole Interaction Induced Rigid-Flexible Coupling SEI for Ultrastable Sodium Storage of Microsized Sn Anode

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Tin (Sn) anodes offer high theoretical capacity for sodium-ion batteries.
• Significant volume expansion during cycling causes rapid capacity degradation in Sn anodes.

Purpose of the Study:

• To develop a stable solid-electrolyte interphase (SEI) for tin anodes.
• To mitigate volume variation and enhance the cycling stability of sodium-ion batteries.

Main Methods:

• Engineered solvation chemistry using solvents with varying solvation abilities.
• Promoted cooperative decomposition of anions and solvents to form a hybrid SEI.
• Investigated the SEI's mechanical robustness and chemical stability.

Main Results:

• Generated a mechanically robust and chemically stable organic-inorganic hybrid SEI.
• Achieved high capacity retention (83.31% after 1000 cycles) for microsized Sn anodes.
• Demonstrated superior rate performance (270.4 mAh g^-1 at 4.0 A g^-1) and a full cell energy density of 235.3 Wh kg^-1.

Conclusions:

• The developed SEI effectively suppresses volume variation and electrolyte decomposition.
• This strategy provides a viable pathway for improving sodium storage in high-volume-change anode materials.
• Highlights the potential of rigid-flexible coupling SEI for advanced battery performance.