Thin Film Physics, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping, Sweden.
Department of Materials Science and Engineering, Drexel University, Philadelphia, Pennsylvania 19104, USA.
Nat Commun. 2017 Apr 25;8:14949. doi: 10.1038/ncomms14949.
The exploration of two-dimensional solids is an active area of materials discovery. Research in this area has given us structures spanning graphene to dichalcogenides, and more recently 2D transition metal carbides (MXenes). One of the challenges now is to master ordering within the atomic sheets. Herein, we present a top-down, high-yield, facile route for the controlled introduction of ordered divacancies in MXenes. By designing a parent 3D atomic laminate, (MoSc)AlC, with in-plane chemical ordering, and by selectively etching the Al and Sc atoms, we show evidence for 2D MoC sheets with ordered metal divacancies and high electrical conductivities. At ∼1,100 F cm, this 2D material exhibits a 65% higher volumetric capacitance than its counterpart, MoC, with no vacancies, and one of the highest volumetric capacitance values ever reported, to the best of our knowledge. This structural design on the atomic scale may alter and expand the concept of property-tailoring of 2D materials.
二维固体的探索是材料发现的一个活跃领域。该领域的研究为我们提供了从石墨烯到二硫化物，以及最近的二维过渡金属碳化物（MXenes）等各种结构。现在的挑战之一是掌握原子层内的有序性。在此，我们提出了一种自上而下、高产率、简便的方法，可在 MXenes 中可控地引入有序的双空位。通过设计具有面内化学有序性的母体 3D 原子层压板（MoSc）AlC，并选择性地刻蚀 Al 和 Sc 原子，我们证明了具有有序金属双空位和高电导率的二维 MoC 片的存在。在约 1,100 F cm 处，这种二维材料的体积电容比具有空位的无空位 MoC 高 65%，据我们所知，这是迄今为止报道的最高体积电容值之一。这种原子尺度上的结构设计可能会改变和扩展二维材料性能调整的概念。
