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.

中文翻译：

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超声辅助的Li + / Na +共嵌入石墨剥落成几层石墨烯的剥落。

在这项工作中，我们通过采用超声方法辅助的Li + / Na +共嵌入剥离技术开发了一种用于多层石墨烯的新方法。实验在300 W的超声波功率和40 kHz的频率下进行，没有任何有机溶剂的参与。深入研究了Li + / Na +比例对石墨剥落的影响。脱落的石墨烯纳米片（UGN）的结构和形态通过一系列表征确定。结果表明，在最佳的Li + / Na +比下，脱落的石墨烯纳米片的厚度约为2.38-2.56 nm（约7-8层）。剥落的石墨烯纳米片作为添加剂在油脂中的潜在应用通过四球摩擦测试仪进行了评估。结果表明，相对于纯润滑脂，含0.06 wt％石墨烯的润滑脂的减摩和抗磨性能分别显着提高了21.35％和30.32％。通过检测磨损表面提出了摩擦机理。