蔗糖基硬碳的磷酸脲掺杂策略：构建高首效、高容量的钠离子电池负极材料

In this paper developed a nitrogen-phosphorus co-doped hard carbon anode material (denoted as HC-UP-4%) via molecular-level premixing of a urea phosphate precursor, which significantly enhanced sodium storage performance. Microstructural characterization confirmed that N and P atoms were embedded in the carbon skeleton in a near-monodispersed manner, effectively suppressing particle agglomeration and optimizing sodium-ion transport pathways. Electrochemical tests demonstrated that the material delivered a specific capacity of 310 mAh g?1 at 0.05 C (24% higher than undoped samples) and an initial Coulombic efficiency (ICE) of 77.3% (9.3% improvement over undoped counterparts). Notably, it exhibited a 75% capacity retention after 100 cycles at a high rate of 15 C, with a pseudocapacitive contribution of 84% at 5.0 mV s?1. Mechanistic analysis revealed that pyridinic-N (398.3 eV) and graphitic-N (401.2 eV) synergistically established a dual sodium storage mechanism of "adsorption-intercalation." This mechanism enhanced surface adsorption energy and electronic conductivity, while nitrogen-enriched SEI layers effectively suppressed electrolyte decomposition. This work provides a simple yet efficient doping strategy to simultaneously boost capacity and ICE in carbon-based anodes, demonstrating promising potential for practical applications.