Key Laboratory of Automobile Materials (Jilin University), Ministry of Education, and College of Materials Science and Engineering, Jilin University, Changchun, 130012, China.
Phys Chem Chem Phys. 2019 Feb 20;21(8):4276-4285. doi: 10.1039/c8cp05982a.
We explore the adsorption stability and quantum capacitance of transition metal atoms on silicene based on first-principles calculations. Silicene with a buckled atomic layer has a high surface/volume ratio and silicene-based materials are expected to have potential applications for supercapacitors. We find that the most favorable adsorption sites on pristine silicene are valley sites for Al and Ti, and hollow sites for Ag, Cu and Au, respectively. Among all these systems with the doping of metal atoms, silicene is modulated to possess a quasi-metallic characteristic, accompanied by an appreciable electron transfer and the formation of defect states near the Fermi level. Due to the low density of states near the Fermi level, the quantum capacitance of pristine silicene has been limited. By the doping of metal atoms, especially Ti atoms, with the introduction of localized defect states near the Fermi level, quantum capacitance is found to be enhanced significantly. In addition, the quantum capacitance is found to increase monotonically following the increase of doping concentrations.
我们基于第一性原理计算研究了过渡金属原子在硅烯上的吸附稳定性和量子电容。具有褶皱原子层的硅烯具有高的比表面积/体积比，并且基于硅烯的材料有望在超级电容器中有潜在的应用。我们发现，对于原始硅烯，最有利的吸附位置分别是 Al 和 Ti 的谷位置以及 Ag、Cu 和 Au 的空位置。在所有这些掺杂金属原子的体系中，硅烯被调制为具有类金属特性，伴随着在费米能级附近可观的电子转移和缺陷态的形成。由于费米能级附近的态密度较低，原始硅烯的量子电容受到限制。通过掺杂金属原子，特别是 Ti 原子，在费米能级附近引入局域缺陷态，发现量子电容显著增强。此外，随着掺杂浓度的增加，量子电容也被发现单调增加。
