Tailoring Pseudo‐Graphitic Domain by Molybdenum Modification to Boost Sodium Storage Capacity and Durability for Hard Carbon

Abstract Hard carbon (HC) stands out as the most prospective anode for sodium‐ion batteries (SIBs) with significant potential for commercial applications. However, some long‐standing and intractable obstacles, like low first coulombic efficiency (ICE), poor rate capability, storage capacity, and cycling stability, have severely hindered the conversion process from laboratory to commercialization. The above‐mentioned issues are closely related to Na + transfer kinetics, surface chemistry, and internal pseudo‐graphitic carbon content. Herein, constructing molybdenum‐modified hard carbon solid spheres (Mo 2 C/HC‐5.0), both the ion transfer kinetics, surface chemistry, and internal pseudo‐graphitic carbon content are comprehensively improved. Specifically, Mo 2 C/HC‐5.0 with higher pseudo‐graphitic carbon content provides a large number of active sites and a more stable layer structure, resulting in improved sodium storage capacity, rate performance, and cycling stability. Moreover, the lower defect density and specific surface area of Mo 2 C/HC‐5.0 further enhance ICE and sodium storage capacity. Consequently, the Mo 2 C/HC‐5.0 anode achieves a high capacity of 410.7 mA h g −1 and an ICE of 83.9% at 50 mA g −1 . Furthermore, the material exhibits exceptional rate capability and cycling stability, maintaining a capacity of 202.8 mA h g −1 at 2 A g −1 and 214.9 mA h g −1 after 800 cycles at 1 A g −1 .