Insights into the Na+ Storage Mechanism of Phosphorus-Functionalized Hard Carbon as Ultrahigh Capacity Anodes
Insights into the Na+ Storage Mechanism of Phosphorus-Functionalized Hard Carbon as Ultrahigh Capacity Anodes
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DOI：
10.1002/aenm.201702781
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发表时间：
2018-06-25
影响因子：
27.8
通讯作者：
Lu, Jun
中科院分区：
文献类型：
--
作者：
Li, Yu;Yuan, Yifei;Lu, Jun
硬碳作为钠离子电池的典型负极材料，因其成本低、可再生性好而备受关注。在此，通过静电纺丝技术合成具有特定蜂窝状形貌的磷官能化硬碳。作为贮钠阳极材料，其可逆容量为393.4mAh·g（-1），100次循环后容量保持率高达98.2%。根据第一性原理计算，磷掺杂后石墨层中P=O和P-C键的形成增强了Na的吸附，从而提高了阳极的比容量。此外，费米能级附近的电子密度的增加主要是由O原子而不是P原子引起的。
Hard carbon as a typical anode material for sodium ion batteries has received much attention in terms of its low cost and renewability. Herein, phosphorus-functionalized hard carbon with a specific honeycomb briquette shaped morphology is synthesized via electrospinning technology. When applied as an anode material for Na+ storage, it exhibits an impressively high reversible capacity of 393.4 mA h g(-1) with the capacity retention up to 98.2% after 100 cycles. According to first-principle calculation, the ultrahigh capacity of the as-prepared anode is ascribed to the enhancement of Na-absorption through formation of P=O and P-C bonds in graphitic layers when doped with phosphorus. Moreover, the increase of electron density around the Fermi level is found to be mainly caused by O atoms instead of P atoms.