Tailoring Carbon Vacancies by Conformational Pre‐Organization Enables Hard Carbon Anodes Toward Ultra‐Long Cycle Life

ABSTRACT Hard carbon is regarded as the most promising anode material for sodium‐ion batteries; however, its intrinsically sluggish kinetics and unstable electrode/electrolyte interphase during cycling fundamentally restrict its rate capability and cycling stability. To overcome these issues, we propose a strategy for tailoring carbon vacancies via conformational pre‐organization of the precursor architecture. Specifically, impurity atoms in the precursor serve as anchoring sites to introduce carbon vacancies that facilitate rapid Na + diffusion. Owing to their localized negative charges, these vacancies preferentially capture Na + while excluding coordinating solvents, homogenizing the interfacial electric field, and diminishing the charge‐transfer resistance. This synergistic effect reinforces interfacial stability and promotes low‐temperature ion‐transport kinetics, leading to markedly improved rate capability and cycling durability. Consequently, the optimized hard carbon anodes deliver an ultra‐long cycle life, achieving 16 000 and 10 000 cycles at 1.0 and 5.0 A g −1 , respectively. Even at −20°C, the advanced anode maintains a capacity retention of 92.40% after 800 cycles at 0.1 A g −1 , further demonstrating its excellent cycling stability. Furthermore, the full cells assembled with Na 3 V 2 (PO 4 ) 3 retain 79.74% of their initial capacity after 3200 cycles at 10C. This work establishes a design paradigm for engineering hard carbon anodes with ultra‐long cycling durability.