Nanoburl Graphites. Issue 17 (18th March 2021)

• Record Type: Journal Article
• Authors: Lin, Kunpeng; Fang, Hailiang; Gao, Ang; Yu, Hui; Wang, Lianjun; Yu, Qian; Gu, Lin; Zhang, Qinghua; Li, Jianlin; Jiang, Wan
• Is Part Of: Advanced materials. Volume 33:Issue 17(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-03-18
• Subjects: graphite flakes -- graphite onions -- nanoburls -- pseudo‐Schottky junctions; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202007513
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: A critical challenge for the application of graphite is low strength, which originates from the easy cleavage of graphite (0002) planes. Inspired by the burl strengthening mechanism observed in tree trunks, nanodiamond particles converted into graphite onions are used as "nanoburls" embedded in graphite (0002) lattice planes to eliminate the graphite (0002) plane cleavage of bulk graphites prepared by spark plasma sintering from graphite powders. Covalent bonds are built between carbon atoms by sp 3 hybridization at the interface between the graphite onions and flakes, which triggers an electron redistribution to form positive/negative charge domains within. Thus, pairs of pseudo‐Schottky junctions are created by the hybridization, which further enhances the bonding between the graphite onions and flakes. With these bonding mechanisms, and with voids between the graphite powders filled in by the volume expansion associated with the change of nanodiamonds to the graphite onions, the loose compaction of graphite powder becomes consolidated at 1700 °C. The proposed nanoburl mechanism shows its potential and bestows the nanoburl graphites with strength five times that of conventional graphites prepared from graphite powders. The concept of nanoburl strengthening can be important in the microstructural design and property enhancement of other layered materials. Abstract : Inspired by the strengthening mechanism of burls in tree trunks, nanodiamond particles converted into graphite onions are used as "nanoburls" that are embedded in graphite (0002) planes to stop cleavage along the graphite (0002) planes, significantly strengthening the bulk graphites.