Ultrasound-assisted Li+/Na+ co-intercalated exfoliation of graphite into few-layer graphene

Zhi-Lin Cheng; Ying-Chao Kong; Lei Fan; Zan Liu

doi:10.1016/j.ultsonch.2020.105108

Ultrasound-assisted Li⁺/Na⁺ co-intercalated exfoliation of graphite into few-layer graphene

Ultrason Sonochem. 2020 Sep:66:105108. doi: 10.1016/j.ultsonch.2020.105108. Epub 2020 Mar 27.

Authors

Zhi-Lin Cheng¹, Ying-Chao Kong², Lei Fan², Zan Liu²

Affiliations

¹ School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China. Electronic address: zlcheng224@126.com.
² School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China.

PMID: 32247231
DOI: 10.1016/j.ultsonch.2020.105108

Abstract

In this work, we developed a novel approach for few-layer graphene by employing Li⁺/Na⁺ co-intercalated exfoliation assisted by ultrasound method. The experiments were conducted under the ultrasonic power of 300 W and the frequency of 40 kHz without the participation of any organic solvent. The effect of Li⁺/Na⁺ proportion on the exfoliation of graphite was intensively investigated. The structure and morphology of the as-exfoliated graphene nanosheets (UGN) was determined by a series of characterizations. The results showed that the thicknesses of the as-exfoliated graphene nanosheets were about 2.38-2.56 nm (about 7-8 layers) at the optimal Li⁺/Na⁺ ratio. The potential application of the as-exfoliated graphene nanosheets as additive in grease was evaluated by four-ball friction tester. The results demonstrated that the antifriction and antiwear performances of the grease with 0.06 wt% graphene were significantly improved by 21.35% and 30.32% relative to pure grease, respectively. The friction mechanism was proposed by detecting the worn surfaces.

Keywords: Anti-friction; Exfoliation; Graphene; Nanosheets; Ultrasound.