Li Tao, Bai Xue, Gulzar Umair, Capiglia Claudio, Bai Yu-Jun, Proietti Zaccaria Remo
Department of Informatics, Bioengineering, Robotics and Systems Engineering (DIBRIS), University of Genova, via Opera Pia 13, Genova 16145, Italy.
Istituto Italiano di Tecnologia, via Morego 30, Genova 16163, Italy.
ACS Omega. 2019 May 8;4(5):8312-8317. doi: 10.1021/acsomega.9b00448. eCollection 2019 May 31.
In the present work, we report, for the first time, a novel one-step approach to prepare highly graphitized carbon (HGC) material by selectively etching calcium from calcium carbide (CaC) using a sulfur-based thermo-chemical etching technique. Comprehensive analysis using X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and N adsorption-desorption isotherms reveals a highly graphitized mesoporous structure for the CaC-derived carbon with a specific surface area of 159.5 m g. Microscopic analysis displays micron-scale mesoporous frameworks (4-20 μm) with a distinct layered structure along with agglomerates of highly graphitized nanosheets (about 10 nm in thickness and 1-10 μm lateral size). The as-prepared HGC is investigated for the role of an anode material for lithium- and sodium-ion batteries. We found that HGC exhibits good lithium storage performance in the 0.01-1.5 V range (reversible capacity of 272.4 mA h g at 50 mA g after 100 cycles and 214.2 mA h g at 500 mA g after 500 cycles), whereas, when sodium is considered, we observed a drop in the overall electrochemical performance owing to the high graphitization degree. More importantly, the present study provides a perspective approach to fabricate HGC via a simple, cost-effective, and efficient synthetic route using CaC and sulfur as reactants.
在本工作中，我们首次报道了一种新颖的一步法，通过使用基于硫的热化学蚀刻技术从碳化钙（CaC）中选择性蚀刻钙来制备高度石墨化碳（HGC）材料。利用X射线衍射、拉曼光谱、X射线光电子能谱和N吸附-脱附等温线进行的综合分析表明，CaC衍生碳具有高度石墨化的介孔结构，比表面积为159.5 m²/g。微观分析显示出微米级的介孔框架（4-20μm），具有独特的层状结构以及高度石墨化纳米片的团聚体（厚度约10nm，横向尺寸为1-10μm）。对所制备的HGC作为锂离子和钠离子电池负极材料的作用进行了研究。我们发现，HGC在0.01-1.5V范围内表现出良好的锂存储性能（在100次循环后，50mA/g时的可逆容量为272.4 mA h/g，在500次循环后，500mA/g时为214.2 mA h/g），而当考虑钠时，由于高石墨化程度，我们观察到整体电化学性能有所下降。更重要的是，本研究提供了一种通过使用CaC和硫作为反应物的简单、经济高效的合成路线来制备HGC的前瞻性方法。
