Anion Pillars Enable High Energy Density Sodium Dual-Ion Battery With Ultra-Long Cycle Life

Area of Science:

• Energy Storage Materials
• Electrochemistry
• Materials Science

Background:

• Sodium dual-ion batteries (SDIBs) offer low cost and high voltage but suffer from graphite cathode structural instability.
• This instability limits long-term performance and hinders large-scale SDIB applications.
• Developing stable cathode materials is crucial for advancing SDIB technology.

Purpose of the Study:

• To introduce a novel anion pillar strategy for stabilizing graphite cathodes in SDIBs.
• To enhance the structural integrity and electrochemical performance of graphite cathodes.
• To overcome the limitations of structural collapse in graphite during battery cycling.

Main Methods:

• Anion pillar strategy applied to the interlayer of graphite cathodes.
• Electrochemical performance testing, including specific capacity and cycling stability.
• Analysis of structural integrity and stability of anion pillars within the graphite structure.

Main Results:

• Achieved a high specific capacity of 162 mAh g^-1 at 200 mA g^-1, with an energy density of 560 Wh kg^-1.
• Maintained 101 mAh g^-1 at 2000 mA g^-1 with 74.0% capacity retention after 15,500 cycles.
• Demonstrated exceptional long-term stability with a low capacity decay rate of 0.0017% per cycle and stable anion pillars.

Conclusions:

• The anion pillar strategy effectively expands and stabilizes graphite layer spacing, preventing structural collapse.
• This approach significantly improves the electrochemical performance and cycle life of SDIBs.
• Presents a promising strategy for developing high-performance and durable graphite cathodes for next-generation energy storage systems.