Shan Yaqi, Wu Jihao, Zhang Zhe, Yang Juan
School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, PR China.
School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, PR China.
J Colloid Interface Sci. 2025 Dec;699(Pt 1):138191. doi: 10.1016/j.jcis.2025.138191. Epub 2025 Jun 12.
The closed-pore structure and surface properties are crucial for enhancing the low-voltage platform capacity (<0.1 V) of hard carbon (HC) anodes for sodium-ion batteries (SIBs). Nevertheless, the lack of simple yet facile strategies for the fabrication of HC with fast sodium ion (Na) storage kinetics has severely impeded the development of high-performance SIBs. Herein, a straightforward strategy is proposed to fabricate HC anodes with high specific capacity and superior rate performance by employing magnesium nitrate (MN)-assisted oxidation coupled with a surface coating of pitch-derived carbon layer. The oxidizing properties of MN are leveraged to introduce oxygen-containing functional groups into the porous carbon frameworks, thereby impeding the formation of graphitic structures during the high-temperature carbonization process. Simultaneously, the metal oxide nanocrystals generated by the decomposition of MN and the surface coating of the carbon layer are capable of tuning the microstructure and surface properties of the HC anodes. The optimized HC sample (PC-0.5-1300) exhibits a high reversible capacity of 277.6 mAh g at 0.1 A g with an infusive platform capacity of 181.2 mAh g and superior rate capability of 185.0 mAh g at a high output current density of 5 A g, highlighting a great potential of Na storage. Impressively, the PC-0.5-1300 anode also delivers good long-term cycling stability with a capacity retention rate of 74.9 % after 2000 cycles at 1 A g. This work provides a simple oxidation coupled with a surface coating method for regulating the electrochemical performance of HC anode for SIBs.
对于钠离子电池（SIB）的硬碳（HC）负极而言，其闭孔结构和表面性质对于提升低电压平台容量（<0.1 V）至关重要。然而，缺乏简单易行的策略来制备具有快速钠离子存储动力学的HC，这严重阻碍了高性能SIB的发展。在此，提出了一种直接的策略，通过采用硝酸镁（MN）辅助氧化并结合沥青衍生碳层的表面包覆来制备具有高比容量和优异倍率性能的HC负极。利用MN的氧化性质将含氧官能团引入多孔碳骨架中，从而在高温碳化过程中阻碍石墨结构的形成。同时，由MN分解产生的金属氧化物纳米晶体和碳层的表面包覆能够调节HC负极的微观结构和表面性质。优化后的HC样品（PC-0.5-1300）在0.1 A g下表现出277.6 mAh g的高可逆容量，其注入平台容量为181.2 mAh g，在5 A g的高输出电流密度下具有185.0 mAh g的优异倍率性能，突出了其巨大的钠存储潜力。令人印象深刻的是，PC-0.5-1300负极在1 A g下经过2000次循环后也具有良好 的长期循环稳定性，容量保持率为74.9%。这项工作提供了一种简单的氧化结合表面包覆方法来调节SIB的HC负极的电化学性能。
