Nitrogen-rich porous aromatic framework cathode for wide-temperature sodium-organic batteries

Sodium-ion batteries (SIBs) are considered to have broad application prospects in large-scale energy storage fields due to their advantages such as abundant resources and low cost. However, the extensive use of inorganic electrode materials may exert tremendous pressure on resource utilization and battery recycling. In contrast, organic electrode materials have advantages such as abundant resources, environmental friendliness, and easier recycling and processing. Therefore, they are regarded as the research frontier and focus of the next generation of green batteries. However, organic electrode materials have the problem of poor cycling stability due to their easy solubility in the electrolyte.

Recently, the team ingeniously combined SIBs with organic batteries, and constructed sodium-organic batteries using molecular engineering strategies. A porous aromatic framework cathode with nitrogen-rich structure motif was constructed. Its rigid skeleton structure not only inhibits dissolution in the electrolyte but also enhances chemical stability, thereby demonstrating excellent cycling stability with 92% reversible capacity after 1000 cycles. Furthermore, the introduction of the HATN motif increased the abundant C=N structural unit as highly reversible redox active centers, which could achieve efficient sodium ion storage and release a reversible specific capacity of 145.2 mAh g^-1. Meanwhile, the introduction of nitrogen-rich units reduces the lowest unoccupied molecular orbital energy level, thereby increasing the redox potential of the material for storing sodium ions. Interestingly, this sodium-organic battery exhibits impressive electrochemical performance over a wide temperature range from -20 °C to 50 °C. This research not only verified the crucial role of nitrogen-rich materials in enhancing electrochemical performance, but also provided a clear and feasible design concept for developing sodium-organic batteries with high potential, high energy density and wide temperature range, which will strongly promote the development of high-performance and sustainable SIBs and meet the growing energy storage demands in the future.