N-Heteroaromatic Hydrocarbon π-Conjugated Porous Polymers for High-Rate-Performance Sodium-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Porous organic polymers (POPs) are promising for sodium-ion battery (SIB) electrodes due to their eco-friendliness and tunable pores.
• Current POPs require improved capacity and rate performance for practical SIB applications.

Purpose of the Study:

• To synthesize and characterize a novel conjugated porous polymer (PQ-POP) for enhanced SIB electrode performance.
• To investigate the electrochemical properties and sodium ion storage mechanism of PQ-POP.

Main Methods:

• Synthesis of PQ-POP via a simple condensation reaction.
• Electrochemical characterization including capacity, rate performance, and cycling stability tests.
• In situ FTIR and XPS experiments to elucidate the sodium ion storage mechanism.

Main Results:

• PQ-POP exhibits a high reversible specific capacity of 245 mAh g^-1.
• Remarkable cycling stability with nearly 100% capacity retention after 1000 cycles at 4 A g^-1.
• A full cell (PQ-POP//Na₃V₂(PO₄)₃) maintained 101 mAh g^-1 at 3 A g^-1 with high coulombic efficiency.

Conclusions:

• The conjugated, N-containing structure of PQ-POP enhances conductivity, charge transfer, and stability.
• PQ-POP demonstrates excellent electrochemical performance, outperforming many similar materials for SIBs.
• This study highlights PQ-POP's potential for advanced energy storage and provides insights for designing future POP electrodes.