Hard carbons (HCs) possess high lithium/sodium storage capacities, which however suffer from low electric conductivity and poor ion diffusion kinetics. An efficient structure design with appropriate heteroatoms doping and optimized graphitic/defective degree is highly desired to tackle these problems. This work reports a new design of N‐doped HC nanoshells (N‐GCNs) with homogeneous defective nanographite domains, fabricated through the prechelation between Ni²⁺ and chitosan and subsequent catalyst confined graphitization. The as‐prepared N‐GCNs deliver a high reversible lithium storage capacity of 1253 mA h g⁻¹, with outstanding rate performance (175 mA h g⁻¹ at a high rate of 20 A g⁻¹) and good cycling stability, which outperforms most state‐of‐the‐art HCs. Meanwhile, a high reversible sodium storage capacity of 325 mA h g⁻¹ is also obtained, which stabilizes at 174 mA h g⁻¹ after 200 cycles. Density functional theory calculations are performed to uncover the coupling effect between heteroatom‐doping and the defective nanographitic domains down to the atomic scale. The in situ Raman analysis reveals the “adsorption mechanism” for sodium storage and the “adsorption–intercalation mechanism” for lithium storage of N‐GCNs.

中文翻译：

---

N掺杂和有缺陷的纳米石墨区耦合的硬碳纳米壳，用于高性能锂/钠存储

硬碳（HCs）具有较高的锂/钠存储容量，但是其电导率较低且离子扩散动力学较差。为了解决这些问题，非常需要具有适当杂原子掺杂和优化的石墨/缺陷度的有效结构设计。这项工作报告了一种新设计的具有均匀缺陷纳米石墨域的N掺杂HC纳米壳（N-GCN），其通过在Ni ²⁺和壳聚糖之间进行预螯合以及随后的催化剂限制的石墨化来制造。所制备的N- GCNs递送1253毫安汞柱高的可逆锂储存容量^-1，以优异的倍率性能（175毫安汞柱^-1在20甲克率高^-1）和良好的循环稳定性，胜过大多数最新的HC。同时，还获得了325mA hg ^-1的高可逆钠存储容量，其在200个循环后稳定在174 mA hg ^-1。进行密度泛函理论计算以揭示杂原子掺杂与低至原子级的有缺陷的纳米石墨域之间的耦合效应。原位拉曼分析揭示了N-GCN的钠存储的“吸附机理”和锂存储的“吸附-嵌入机理”。