1. Center for NanochemistryBeijing Science and Engineering Center for NanocarbonsBeijing National Laboratory for Molecular SciencesCollege of Chemistry and Molecular EngineeringPeking University Beijing 100871 P. R. China
2. Beijing Graphene Institute (BGI) Beijing 100095 P. R. China
3. Science and Technology on Advanced Ceramic Fibers and Composites LaboratoryCollege of Aerospace Science and EngineeringNational University of Defense Technology Changsha 410000 P. R. China
4. Institute of Engineering ThermophysicsChinese Academy of Sciences Beijing 100190 P. R. China