Exploiting high-performance yet low-cost hard carbon anodes is crucial to advancing the state-of-the-art sodium-ion batteries. However, the achievement of superior initial Coulombic efficiency (ICE) and high Na-storage capacity via low-temperature carbonization remains challenging due to the presence of tremendous defects with few closed pores. Here, a facile hybrid carbon framework design is proposed from the polystyrene precursor bearing distinct molecular bridges at a low pyrolysis temperature of 800°C via in situ fusion and embedding strategy. This is realized by integrating triazine- and carbonyl-crosslinked polystyrene nanospheres during carbonization. The triazine crosslinking allows in situ fusion of spheres into layered carbon with low defects and abundant closed pores, which serves as a matrix for embedding the well-retained carbon spheres with nanopores/defects derived from carbonyl crosslinking. Therefore, the hybrid hard carbon with intimate interface showcases synergistic Na ions storage behavior, showing an ICE of 70.2%, a high capacity of 279.3 mAh g⁻¹, and long-term 500 cycles, superior to carbons from the respective precursor and other reported carbons fabricated under the low carbonization temperature. The present protocol opens new avenues toward low-cost hard carbon anode materials for high-performance sodium-ion batteries.

中文翻译：

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源自聚苯乙烯的混合硬碳框架具有独特的分子交联，可增强钠储存

利用高性能且低成本的硬碳阳极对于发展最先进的钠离子电池至关重要。然而，由于存在大量缺陷和很少的闭孔，通过低温碳化实现优异的初始库仑效率（ICE）和高钠存储容量仍然具有挑战性。在这里，通过原位融合和嵌入策略，在 800°C 的低热解温度下，从具有不同分子桥的聚苯乙烯前体提出了一种简便的混合碳骨架设计。这是通过在碳化过程中整合三嗪和羰基交联的聚苯乙烯纳米球来实现的。三嗪交联允许球体原位融合成具有低缺陷和丰富闭孔的层状碳，其作为嵌入具有源自羰基交联的纳米孔/缺陷的良好保留的碳球的基质。^{因此，具有紧密界面的混合硬碳表现出协同的Na离子存储行为，表现出70.2%的ICE、279.3 mAh g -1}的高容量和长期500次循环，优于各自前驱体和其他报道的碳。在较低的碳化温度下制备的碳。本协议为高性能钠离子电池的低成本硬碳阳极材料开辟了新途径。