Abstract Soft carbons with high conductivity have potential advantages as high-performance sodium-ion battery anodes, however, they suffer from small interlayer distance and low hereoatom content. In this work, porous carbon nanosheets (PCNS1000) with tunable microstructure, pore structure and chemical composition were prepared from coal tar pitch through a two-step process involving NaCl template method and NH 3 treatment. PCNS1000 possesses an expanded interlayer distance of 3.82 A, mesopore structure with average pore size of 5.7 nm, and a high nitrogen content of 4.17 wt%. Moreover, PCNS1000 retains soft carbon feature to a certain extent and consequent relative high conductivity. Benefiting from its appropriate structure and chemical composition, PCNS1000 exhibits a high reversible capacity of 270 mAh g −1 at 100 mA g −1 in sodium-ion half cells and excellent rate capability of 124 mAh g −1 at large current of 10 A g −1 . After an ultralong charge-discharge cycling of 10,000 times, a high capacity retention of 86% was achieved, indicating its excellent electrochemical stability. The full cell assembled by Na 3 V 2 (PO 4 ) 3 cathode and PCNS1000 anode delivers a high capacity of 265 mAh g −1 at 100 mA g −1 , with a good cycling ability of 89% capacity retention after 100 cycles at 1.0 A g −1 .

中文翻译：

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具有扩展层间距的沥青衍生的 N 掺杂多孔碳纳米片作为高性能钠离子电池负极

摘要 具有高电导率的软碳作为高性能钠离子电池负极具有潜在优势，但其存在层间距小、原子含量低等缺点。在这项工作中，通过涉及 NaCl 模板法和 NH 3 处理的两步法，以煤焦油沥青为原料制备了具有可调微观结构、孔结构和化学成分的多孔碳纳米片 (PCNS1000)。PCNS1000 具有 3.82 A 的扩展层间距、平均孔径为 5.7 nm 的中孔结构和 4.17 wt% 的高氮含量。此外，PCNS1000 在一定程度上保留了软碳特性，从而具有相对较高的导电性。得益于其适当的结构和化学成分，PCNS1000 在钠离子半电池中在 100 mA g -1 时表现出 270 mAh g -1 的高可逆容量和在 10 A g -1 大电流下 124 mAh g -1 的优异倍率性能。经过10,000次超长充放电循环后，实现了86%的高容量保持率，表明其优异的电化学稳定性。由 Na 3 V 2 (PO 4 ) 3 正极和 PCNS1000 负极组装的全电池在 100 mA g -1 下提供 265 mAh g -1 的高容量，在 1.0 下循环 100 次后容量保持率为 89% A g -1 。