School of Materials and Energy, Center of Emerging Material and Technology, Guangdong University of Technology , Guangzhou 510006, China.
Department of Mechanical and Biomedical Engineering, City University of Hong Kong , 83 Tat Chee Avenue, Kowloon Tong, Hong Kong.
ACS Appl Mater Interfaces. 2017 Oct 4;9(39):33876-33886. doi: 10.1021/acsami.7b09808. Epub 2017 Sep 25.
Nitrogen-doped hierarchical porous carbon and carbon nanotube hybrids (N-HPC-CNTs) are fabricated by simple pyrolysis of the N-rich raw material melamine-formaldehyde (MF) resin in the presence of nano-CaCO and a bimetallic combination of Fe-Co catalyst. During carbonization, nano-CaCO acts as a template for creating a hierarchical porous carbon, and the N atoms originated from MF resin are in situ doped into the carbon matrix simultaneously. Meanwhile, volatile gases generated by the thermal decomposition of MF resin could serve as carbon and nitrogen sources to grow nitrogen-doped CNTs on HPC. The growth mechanism is the same as that for conventional chemical vapor deposition (CVD) growth of CNTs on the metal catalysts, but the technological requirements are obviously not as harsh as those for the CVD method. Low-cost raw materials and simple equipment are sufficient for the growth. Moreover, the density and length of the CNTs are tunable, which can be simply adjusted via applying different amounts of Fe-Co catalysts. Such an N-doped hybrid structured carbon with mesopores can not only effectively prompt the physical and chemical adsorption of polysulfides but also ensures a fast electron transfer because of the incorporation of CNTs, which provides sufficient conducting pathways and effective connections between the CNTs and HPC. Furthermore, CNTs grown on HPC can act as physical barriers to block the large pores on HPC, thereby reducing the polysulfide loss. Benefiting from the advantages, the N-HPC-CNT hybrids are a desirable host prospect for Li-S batteries.
氮掺杂分级多孔碳和碳纳米管杂化材料（N-HPC-CNTs）是通过在纳米 CaCO 和双金属 Fe-Co 催化剂存在下，简单地热解富氮原料三聚氰胺-甲醛（MF）树脂制备的。在碳化过程中，纳米 CaCO 作为创建分级多孔碳的模板，同时来自 MF 树脂的 N 原子原位掺杂到碳基质中。同时，MF 树脂热分解产生的挥发性气体可以作为碳和氮源，在 HPC 上生长氮掺杂 CNTs。生长机制与传统 CVD 方法中 CNT 在金属催化剂上的生长机制相同，但技术要求显然不如 CVD 方法苛刻。只需使用低成本的原材料和简单的设备即可满足生长要求。此外，CNTs 的密度和长度是可调的，只需通过施加不同量的 Fe-Co 催化剂即可简单地进行调整。这种具有介孔的氮掺杂杂化结构碳不仅可以有效地促进多硫化物的物理和化学吸附，而且由于 CNT 的掺入还可以确保快速的电子转移，因为 CNT 提供了充足的导电途径和 CNT 与 HPC 之间的有效连接。此外，在 HPC 上生长的 CNT 可以作为物理屏障来阻止 HPC 上的大孔，从而减少多硫化物的损失。由于这些优点，N-HPC-CNT 杂化材料是 Li-S 电池的理想宿主前景。
