Two-dimensional (2D) van der Waals layered materials have been widely used as lubricant. Penta-graphene (PG), a 2D carbon allotrope exclusively composed of irregular carbon pentagons has recently been predicted to have superlubricating property. In the present study, by combining the molecular dynamics simulation and first-principles calculations, we investigated the frictional property of PG in both commensurate and incommensurate contacts. Our calculations show the ultra-low friction at the interface of relatively rotated bilayer PG with twist angles of more than 10° away from the commensurate configuration. Meanwhile, our calculations demonstrate the isotropy of the ultra-low friction at the interface of incommensurate contact, in contrast to the anisotropic of the commensurate contacting interface. Additionally, the evolution of friction force and the fluctuation of potential energy along sliding path correlate closely with the interface’s structure. The energetics and charge density explain the difference between the friction at the interfaces of the commensurate and incommensurate contacts. Not only that, we found the correlation between the intrinsic structural feature and interlayer binding energy. Importantly, our findings on the retainment of the ultra-low friction under work conditions indicates that the superlubricating state of PG has good practical adaptability.

二维（2D）范德华层状材料已被广泛用作润滑剂。五石墨烯（PG）是一种仅由不规则碳五边形组成的二维碳同素异形体，最近被预测具有超润滑性能。在本研究中，通过结合分子动力学模拟和第一性原理计算，我们研究了PG在等量和非等量接触中的摩擦特性。我们的计算表明，相对旋转的双层 PG 的界面具有超低摩擦，其扭转角与相应的配置相差超过 10°。同时，我们的计算证明了不相称接触界面处超低摩擦的各向同性，而不是相称接触界面的各向异性。此外，摩擦力的演变和势能沿滑动路径的波动与界面的结构密切相关。能量学和电荷密度解释了等量接触和不等量接触界面处的摩擦之间的差异。不仅如此，我们还发现了内在结构特征与层间结合能之间的相关性。重要的是，我们在工作条件下保持超低摩擦的研究结果表明，PG的超润滑状态具有良好的实际适应性。