Abstract Motivated by the synthesis of three-dimensional (3D) honeycomb carbon structures and the subsequent theoretical prediction of an energetically more favorable hexagonal carbon phase composed of 28 carbon atoms in the unit cell (hC28) with ordered pores, excellent mechanical properties, and metallic feature, we explore its potential for a Na-ion battery (NIB) anode material. Using density functional theory based calculations, we find that hC28 is a promising candidate whose specific capacity of 717 mAh/g is almost three times larger than that of hard carbon (∼250 mAh/g). In addition, migration barrier of Na ions along the honeycomb channel is only 0.08 eV and the volume change during the charging/discharging process is merely 2.30%, which are much less than those of other carbon-based NIB anode materials. The average voltage is also low (0.36 eV) which can provide high operating voltage when connected to the cathode. These encouraging results would pave the way towards the development of hC28 as NIB anode with high capacity, excellent rate performance, low open-circuit voltage, and long-term cycle life.

中文翻译：

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具有高容量、优异倍率性能和强大稳定性的3D多孔蜂窝碳作为钠离子电池负极材料

摘要 受三维 (3D) 蜂窝状碳结构的合成和随后的理论预测的推动，即在晶胞 (hC28) 中由 28 个碳原子组成的能量更有利的六方碳相具有有序的孔隙、优异的机械性能和金属功能，我们探索了其作为钠离子电池 (NIB) 负极材料的潜力。使用基于密度泛函理论的计算，我们发现 hC28 是一种很有前途的候选材料，其 717 mAh/g 的比容量几乎是硬碳（~250 mAh/g）的三倍。此外，Na离子沿蜂窝通道的迁移势垒仅为0.08 eV，充放电过程中的体积变化仅为2.30%，远小于其他碳基NIB负极材料。平均电压也很低（0. 36 eV)，当连接到阴极时可以提供高工作电压。这些令人鼓舞的结果将为开发 hC28 作为具有高容量、优异倍率性能、低开路电压和长循环寿命的 NIB 负极铺平道路。