1. State Key Laboratory of Tribology in Advanced Equipment & Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
2. Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084, China
3. Institute of Superlubricity Technology, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057, China
4. Laboratory of Advanced Energy Storage Materials & devices, Center for Advanced Materials & Biotechnology, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057, China