Self‑carbonization of rigid planar organic cathode material for efficient sodium-ion battery

Organic carbonyl compounds with high theoretical capacities and designability are promising electrode materials for sodium-ion batteries (SIBs), while their high solubility in electrolytes poses challenges for cycling stability. Herein, a synergistic strategy combining the design of rigid conjugated molecular structures and self‑carbonization is proposed. Specifically, a new organic molecule (DTQP) featuring a planar and rigid conjugated fused-ring structure is designed. The extended conjugated system and abundant heteroatoms enhance intermolecular interactions, facilitating charge transport. Subsequently, a thin carbon layer is constructed on the material surface (DTQP@C) through self‑carbonization, which further inhibits dissolution and improves the cycling stability. As a result, the DTQP@C electrode exhibits a capacity of 213 mA h g^-1 at 100 mA g^-1 and maintains a 91.5% capacity retention rate following 300 cycles in a half-cell. Under the same conditions, the pristine DTQP electrode shows a capacity of 223 mAh g^-1, with a retention rate of only 61% after 100 cycles. Moreover, a full-cell is successfully assembled, delivering a capacity of 75 mAh g^-1 at 1 A g^-1 and achieving a retention rate of 85.3% after 1500 cycles, which demonstrates its potential for practical applications. This research integrates molecular design and self‑carbonization, offering new insights into simultaneously achieving high-rate capability, high capacity, and enhanced stability in sodium-ion batteries.