Long-lifespan Polyanionic Organic Cathodes for Highly Efficient Organic Sodium-ion Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Sodium-ion batteries (SIBs) are a promising alternative to lithium-ion batteries due to sodium's abundance.
• Organic electrode materials offer sustainable and tunable options for SIBs.
• Developing high-performance and stable organic SIBs remains a key challenge.

Purpose of the Study:

• To develop and characterize a novel organic sodium-ion full cell.
• To evaluate the electrochemical performance and cycling stability of the proposed battery system.

Main Methods:

• Fabrication of a full cell using a polyanionic 9,10-anthraquinone-2,6-disulfonate (Na2AQ26DS) cathode and a sodium terephthalate (Na2TP) anode.
• Electrochemical testing including galvanostatic cycling and capacity measurements over a voltage range of 0.5-3.2 V.
• Long-term cycling stability assessment at a current density of 0.5 A g⁻¹ for 1200 cycles.

Main Results:

• The organic Na-ion battery achieved a maximum discharge capacity of 131 mAh g⁻¹ cathode.
• The full cell demonstrated remarkable cycling stability, retaining an average capacity of ≈62 mAh g⁻¹ cathode after 1200 cycles.
• Performance metrics position this organic SIB among the best reported to date.

Conclusions:

• The developed organic Na-ion battery exhibits competitive electrochemical performance and long-term stability.
• Polyanionic anthraquinone derivatives and sodium terephthalate are promising organic materials for advanced sodium-ion energy storage.
• This work contributes to the advancement of sustainable and high-performance organic batteries.