Thermodynamically Self-Limiting Presodiation Inducing Homogeneous Inorganic-Organic Polymer-Skeleton Interphases for...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Cathode-side chemical presodiation is crucial for compensating initial sodium loss in sodium-ion batteries (SIBs).
• Conventional methods suffer from oversodiation, structural degradation, and poor cycling stability, limiting their practical use.

Purpose of the Study:

• To develop a universal and thermodynamically self-limiting chemical presodiation strategy for SIBs.
• To overcome the limitations of conventional presodiation techniques, including oversodiation and the need for strict time control.

Main Methods:

• Synergistic integration of sodium diphenyl ketone (Na-DK) with fluoroethylene carbonate (FEC) for chemical presodiation.
• Utilizing Na-DK for controllable, self-limiting sodium insertion and FEC decomposition to form robust cathode-electrolyte interphases (CEIs).

Main Results:

• Achieved thermodynamically self-limiting sodium insertion, preventing oversodiation and eliminating the need for precise presodiation time control.
• Formed homogeneous inorganic-organic polymer-skeleton CEIs with enhanced mechanical properties.
• Demonstrated exceptional cycling stability for Na3V2(PO4)3 cathodes (93.5% capacity retention after 2000 cycles at 1 C).
• Showcased over twofold capacity enhancement and extended cycle life in full cells compared to commercial counterparts.
• Validated the broad applicability of the strategy across different cathode chemistries, including Na4Fe3(PO4)2P2O7.

Conclusions:

• The proposed Na-DK/FEC presodiation strategy offers a universal, thermodynamically self-limiting, and practical approach for enhancing SIB performance.
• This method significantly improves cycling stability, capacity, and cycle life by preventing oversodiation and forming superior CEIs.
• The demonstrated broad applicability makes this strategy highly promising for the commercialization of advanced sodium-ion batteries.